ABSTRACT It is a live project which involves the design of Test stand for sub assemblies of distributor valves; relay valve is a recent attached of distributor valve. The objective of project is design and fabrication of sub assemblies of distributor valve which helps in rectifying, troubleshooting and periodic overhauling .This makes aware and helps to explain one of the best sophisticated, sophisticated, reliable, efficient braking braking system Fast expanding industrialization of the country needs fast movements of higher safety of men & material. Hence, the relay valve is introduced for distributor valve in Air brake system. previously trains used Vacuum Braking system but right now there are working Air braking system, as it has exceptional advantages over ov er Air brake system Now Air Brakes had under gone many changes it has revolutionized speed reducing braking system with better reliable safety and in exh austibility
HISTORY OF RAIL TRANSPORT IN INDIA Q. When did the first train run in India? The customary answer to this question is 3:35pm on April 16th, 1853, when a train with 14 railway carriages and 400 guests left Bombay's Bori Bunder for Thane, with a 21-gun salute. It was hauled by three locomotives: Sindh, Sultan, and Sahib. The journey took an hour and fifteen minutes.
That, however, was just the first commercial passenger service in India. In fact, a steam loco, Thomason, had been used for hauling construction material in Roorkee for the Solani viaduct in 1851 (it began working there on 22nd December 1851, to be exact). The Solani viaduct construction was a part of the Ganges Canal project, started in 1845. The viaduct had 15 arches and spanned the 4km-wide Solani valley (about 145km north-east of New Delhi). Earth for the approach embankments was transported along light rail lines about 5 to 10 km long from Piran Kaliyar to Roorkee. Standard gauge wagons were used, built from parts brought over from England, and hauled by men and later horses. In late 1851, the locomotive Thomason (named for the engineer on the project) was assembled on the spot from parts transported from Calcutta. It hauled two wagons at a time, at a speed of about 6km/h. It did not last very long, and after about 9 months India's first steam locomotive died a spectacular death with a boiler explosion, reportedly to the delight of the construction workers who had viewed it more as a hindrance than help. Hughes' book states that this was a six-wheeled tank engine, probably a 2-2-2WT built by E. B. Wilson, and of standard gauge. Some details of the wagons and the use of the locomotive are in Sir Proby T Cautley's "Report on the Ganges Canal Works" Works" (3 volumes, 1860). "[The railway is] a triumph, to which, in comparison, all our victories in the East seem tame and commonplace. The opening of the Great Indian Peninsular Railway will be remembered by the natives of India when the battlefields of Plassey, Assaye, Meanee, and Goojerat have become landmarks of history." history." (The Overland Ove rland Telegraph Telegraph and Courier, April 1853)The second locomotive to arrive in India was Falkland (named for a governor of Bombay), used by the contractors of the GIPR for shunting operations on the first line out of Bombay that was being built. It began work on February 23, 1852. Hughes' book suggests that this was also built by E. B. Wilson, and was probably a four-wheeled tank engin enginee (0-4 (0-4-0 -0T? T?)) with with dummy dummy cran cranks ksha haft ft.. It late laterr becam becamee GIPR GIPR loco loco #9. A thir third d
locomotive, Vulcan, is said to have been used by the GIPR for material hauling and shunting duties in 1852 as well. There were also eight more locos from Vulcan Foundry imported by GIPR in 1852 and 1853. On November 18, 1852, a locomotive hauled some coaches on a trial run from Bori Bunder to Thana. This probably counts as the first "real" train to run in India. Q. What was the Guarantee System? What were Guaranteed Railways? In the 1840s, when the first proposals for railways in India were being debated in Great Britain, there was intense lobbying in support of these proposals by banks, traders, shipping companies, and others who had a strong interest in seeing railways be formed in India. These supporters prevailed upon the British Parliament to create the Guarantee System, whereby any company that constructed railways in India was guaranteed a certain rate of interest on its capital investment. This guarantee was honoured by the East India Company which then controlled large parts of India. The railways that were formed with such agreements governing them were called guaranteed railways. Typically, the guarantee was for a return of 5% annually, and the right for the railway company to pull out of the venture and get compensation from the government at any time.
Chronology of railways in India, Part 2 (1832 - 1865)Note: This chronology is intended as a general overview for non-specialists to give them a feel for some of the interesting and complex complex events events that shaped shaped the developme development nt of railwa railways ys in India. India. Many line openings are mentioned to give an idea of the geographic spread of railway services. Dates in most cases are those for when the completed lines were open to traffic; usually sections sections of the line may have been opened years earlier, earlier, and might even have supported supported revenue traffic in parts. Dates are often somewhat uncertain because of varying reports in different sources, or lack of documentation, hence in many cases they may be off by a couple of years. Anyone seeking reliable and specific information and more detail is strongly urged to consult the reference works listed in the guide to historical research and the section on books about IR history
A plan for a rail system in India was first put forward in 1832, but no further steps were taken for more than a decade. In 1844, the Governor-General of India lord Hardinge allowed private entrepreneurs to setup a rail system in India. Two new railway companies were were create created d and the East India India Company Company was asked asked to assist assist them. Interest Interest from investors in the UK led to the rapid creation of a rail system over the next few years. The first train in India became operational on 22-12-1851, and was used for the hauling of constru constructi ction on materi material al in Roorke Roorkee. e. A year year and a half half later later,, on 16-0416-04-1853 1853,, the first first passen passenger ger train train servic servicee was inaugur inaugurated ated betwee between n Boribu Boribunder nder,, Bombay Bombay and thane. thane. Covering a distance of 34km (21 miles), it formally heralded the birth of railways in India. The British government encouraged new railway companies backed by private investors under a scheme that would guarantee an annual return of five percent during the initial years of operation. Once established, the company would be transferred to the government, with the original company retaining operational control. The route mileage of this network was about 14,500 km (9,000 miles) by 1880, mostly radiating inward from the three major port cities of Bombay, Madras and Calcutta. By 1895, India had
started building its own locomotives, and in 1896 sent engineers and locomotives to help build the Uganda Railway. Railway. Soon various independent kingdoms built their own rail systems and the network spread to the regions that became the modern-day states of Assam, Rajasthan and Andhra Pradesh. A Railway board was constituted in 1901, but decision-making power was retained by the viceroy Lord Curzon. The Railway Board operated under aegis of the Department of commerce and Industry and had three members: a government railway official serving as chairman, a railway manager from England and an agent of one of the company railways. For the first time in its history, the Railway began to make a tidy profit. In 1907, almost all the rail companies co mpanies were taken over by the government. The following year, the first electric locomotive appeared. With the arrival of the First World World War, War, the railways were used to meet the needs of the British outside India. By the end of the First World War, the railways had suffered immensely and were in a poor state. The government took over the management of the Railways and removed the link between the financing of the Railways and other governmental revenues in 1920, a practice that continues to date with a separate railway budget. The Second World War severely crippled the railways as trains were diverted to the Middle East, and the railway workshops were converted into munitions workshops. At the time of independence in 1947, a large portion of the railways went to the then newly formed Pakistan. Pakistan. A total of forty-two forty-two separate railway railway systems, systems, including thirtythirtytwo lines owned by the former Indian princely states, were amalgamated as a single unit, which was christened as the Indian Railways. The existing rail networks were abandoned in favor of zones in 1951 and a total of six zones came into being in 1952. As the economy of India improved, almost all railway production units were indigenized. By 1985, steam locomotives were phased out in favor of diesel and electric locomotives. The entire railway reservation system was streamlined with computerization in 1995.
HISTORY OF SOUTH CENTRAL RAILWAY CARRIAGE REPAIR WORKSHOP LALLAGUDA, SECUNDERABAD – 500 017
1. INTRODUCTION:
South Central Railway, Carriage Repair Workshop, Lallaguda, Secunderabad, a premier repair repair worksh workshop op of Indian Indian Railwa Railways ys was establis established hed on 30th September September 1893. This workshop was under the argis of “THE NIZAM GUARANTEED STATE RAILWAYS” for undertaking periodic overhauling and repairs to BE and MG steam locomotives, coaches and wagons. Subsequently it was brought under the preview of “NIZAM STATE RAILW RAILWAYS.” Consequently upon the re-organization of Railways Railwa ys in 1951, this workshop became a integral part of Central Railways, subsequently South Central Railway was formed on 2nd October 1966 it became a major workshop for the zone. It continued to composite workshop for MG and BG rolling stock till 1969 when a repair to MG rolling stock was off loaded to Hubli workshop. With the tapering of Locos and bifurcation of wagons under wagon repair workshop at Guntapalli. Carriage workshop was exclusively meant for undertaking POH of carriages. This workshop occupies an area of 13.97 hectares with 4.25 hectares under cover. It is equipped and supported with full facilities within its premises. Carriage Rep air Workshop Workshop of Lallaguda is one of the few integrated workshops in Indian Railways. In the past decades the workshop carried out periodically overhauling of the BG main line coaches including A/C coaches and backup manufacturing activities like Brake blocks, repairs of springs, maintenance of BD steam cranes. Prime activities of this workshop workshop is periodical periodical overhauling of BG and A/C coaches and corrosion repairs to the coaches with allied activities of manufacturing of carriage components like brake gear items, equalizing stays etc, formation of rakes for express trains, conversion of GS coaches. The other activities carried out in this workshops are 1) Laboratory headed by CMT, 2) Basic Training Center for imparting technical education and implementation of Apprentice Act 1961, and 3) Computer center under supervision of Dy.CME / Sr. EDPM in order to modernize the working system had been a boon. ………………………………………………………………………………………..
South central Railway was formed on 2nd October, 1966 as the 9th zone of the Indian Indian Railway Railways. s. In its thirty thirty-ei -eight ght years years of commit committed ted servic servicee and bath bath breaki breaking ng progress, south central Railway has grown to a modern system of mass transportation fulfilling the aspirations of the passengers/customers and carved a niche for itself in Indian Railways system. Strategically positioned in the southern peninsula this dynamic organization with its headquarters at secunderabad serves the economically vibrant state of Andhra Pradesh, part of Maharashtra, Madhya Pradesh and Tamil Naidu. From the days of steam hauled locomotives and wooden plank seats, south central Railway has a long way modernizing its system with the state of art high powered Diesel and Electric locomotives, high speed telescopic passenger coaches, and higher
axle load wagons, higher capacity track in all important routes, multiple aspect color light signaling with solid state inter locking, micro wave and digital communication system etc. Over the years, south central railway has attained sufficient transportation output with with adequat adequatee infras infrastr tructu ucture re develop developmen mentt and technol technologi ogical cal upgradi upgrading ng to serve serve the region regionss in its jurisd jurisdict iction ion.. Safe Safe operati operation on of trains trains,, expans expansion ion of networ network, k, modern modern passenger amenities, punctuality of trains, courteous service and cleanliness in stations and trains trains remain remain always always the thrust thrust areas of this this railwa railway y. Being Being a servic service-o e-orie riente nted d organization, south central railway provided computerized passenger reservation system at 85 stations/locations covering 96% of the berths available. In the arena of information dissemination to the rail customers, it has provided inter-action voice response system (IVRS) for reservation and train enquiry, national information on movement of trains, passen passenger ger operat operated ed enquiry enquiry termi terminals nals (POET (POET)) with with inform informati ation on on availab availabili ility ty of accommo accommodat dation ion and confir confirmat mation ion and close close circuit circuit televi televisio sion n (CCTV) (CCTV) for real real time time reservation availability. availability. Status at a t all-important stations in its systems. For mass movement of freight, S.C.Railway has introduces high horse powered Diesel and Electric locomotives and high speed, high Axle load Box-N-Wagons. Today, south central railway plays a pivotal role as a catalyst for agricultural and industrial development in the southern peninsula apart from fostering the growth of trade and commerc commercee includ including ing import import/ex /expor portt through through ports ports by connecti connecting ng sea ports ports with with their their hinder land and inland container deports. Its reliable and comfortable passenger services for long and short distance travel by way introducing many super fast and inter city trains helps transform the society by catering to their personal, business, educational and tourism purposes.
BRAKE: Any propelled propelled or self propelled propelled vehicle requires requires provision provision of effective effective braking system for retarding its speed or to bring the vehicle to stationary position as when requires. Higher the speed higher is the braking force. SALIENT FEATURES FOR BRAKE OPERATION OPERATION
Simplicity and convenience in manipulation. Integrity of the system. Reliability of the apparatus. Promptness in response to driver ’s action. Absence of shocks. Simultaneous operation. Constancy in rates of braking. High rates of braking Graduated application. Unlimited applications. Compensation for loading. Constancy in all weathers. Absence of skidding. Immunity from track. There are three types of Brakes have been provided. 1. 2. 3.
Hand Brake System. Automatic Va Vacuum Br Brake Sy System. Air Brake System.
HAND BRAKE: These brakes are provided in all Goods Stock, Guard Vans Vans and Inspection Carriage. It can be used during shunting. PRINCIPLE OF VACUUM BRAKE: Vacuum derives its braking power from atmospheric pressure, which acts against the bottom of the piston when the brakes are applied. In this system, pressure differential is maintained between atmospheric pressure and that of vacuum. VACUUM BRAKE COMPONENTS:
The vacuum cylinder suspended by trunnions from the underframe. Brake shaft. Rigging consisting mainly of Pull rods and Levers. Train Pipe and Pipe connects.
Hand Brake (Lever or Screw type).
VACUUM CYLINDER
Position on the Underframe: Vacuum Cylinder is fitted on the under frame in vertical position in BG and MG stocks but in horizontal position NG stocks due to paucity of space between under frame and rail level.
Sizes (Internal diameter basis) For BG Stocks: 24” 21” 18”
-
For Heavier and high speed vehicles. For Medium weight vehicles. For Light weight vehicles.
For MG & NG Stocks: 18” 15”
-
For Heavier vehicles. For Light weight vehicles.
TYPES OF VACUUM BRAKE:
1)
E – TYPE: In this type of vacuum cylinder, one dome shaped vacuum chamber is provided to increase the the volume of the upper chamber. chamber.
2)
F – TYP TYPE: In this this type type of Vacuu acuum m Cy Cylind linder er,, an an aux auxil iliiary ary cham chambe berr is is pro provi vide ded d which is suspended to the under frame and connected with the top of the piston through a double branch release valve.
AIR BRAKE SYSTEM For application of brakes in railway coaches and wagons with vacuum brake system we firs firstt with withdr draw aw air air from from the the trai train n syst system em(c (cre reat atee vacu vacuum) um) and and then then allo allow w the the atmospheric air to reach below the piston in vacuum cylinder lifting the piston upwards which in turn apply brakes.But in air brake system it is the reverse case.In air brake system we first charge the train system with compressed air to certain predetermined level of air pressure through two pipes named feed pipes and brake pipes.The feed and brake pipes are charged to a pressure of 6.0 and 5.0 kg/cm^2 respectively.When brakes are to be applied the air pressure in brake pipe is reduced by the driver which actuates the distributor valve fitted under every wagon or coach on the train .The distributor valve supplies the compressed air from auxiliary reservoir to one side of the piston in the brake cylinder pushing out the piston rod and applying the brakes.The guard and the passengers can also apply the brakes in case of an emergency .During train partings and accidents
brakes also apply automatically and with higher force than that of vacuum brakes.When the air pressure in brake pipe is restored to the normal pressure,the brakes are released. The brakes can also be manually released after the engine has been detached.After application of brakes in air brake system the brakes remain in on position for hours together. Only those engines which are fitted with the air brake system can only work such trains.Such wagons/coaches can also not be worked with other trains with vacuum brake system
TWIN PIPE SYSTEM:-As SYSTEM:-As already stated stated above each and every brake system has two two air pipes pipes from from one one end end to the the othe otherr end end leng length thwi wise se.. One One pipe pipe is used used to conti continu nuos osly ly charge/feed the compressed air to the auxiliary reservoir and is called as Feed pipe.The second pipe is used for application and releasing of brakes and is termed as Brake pipe.As such this system s ystem is called as Twin pipe system. This system has the following merits:Feed pipe charges charges the Auxiliary Auxiliary reservoir continuosly continuosly and maintains maintains the predetermin predetermined ed air pressure pressure in A.R(Auxiliary A.R(Auxiliary reservoir).On reservoir).On application application of brakes the A.R’S compressed air is fed to the brake cylinder and there is a certain fall in air pressure in A.R due to the same.But the feed pipe immediately/simultaneously charges the A.R and maintains the desired air pressure in A.R.Any number of brake applications releasing may be done by the driver in quick succession, the air pressure in A.R will remain the same i.e; there will be no decrease in the air pressure of A.R. This feature is not possible in case feed pipe is removed/isolated from the Air brake system,because the brake pipe will have to shoulder the burden of feed pipe in addition to his own job.In such an event the charging of A.R will take more time to be ready for subsequent brake applications.Resultantly the application of brakes in quick succession is not possible. In case due to any reason one pipe of a coach or any wagon gets damaged or goes defective,it can be bypassed in twin pipe system and the detachment of the coach or wagon would not be essential as in the case of single pipe system,But in this case the train will be worked as single pipe system. SINGLE PIPE SYSTEM:-In SYSTEM:-In this system there is provision of only one air pipe from one end of a wagon/coach to the other end instead of two pipes.This pipe is called as brake pipe.This brake pipe singularly charges the auxiliary reservoir and also applies and releases the brakes.In this system the driver feels very easy in maintaining/charging the brake pipe only but this is not so advantageous to that of Twin pipe system.In this system the auxiliary reservoir is not charged while the A.R supplies air to brake cylinder.As such brakes in quick succession cannot be applied and released.In case of any damage or defect in the air brake system of any coach/wagon,there is no alternative than to detach such coach/wagon coach/wagon from train train enroute.In enroute.In this system system after emergency emergency application application of brakes the driver shall have to wait for some time to fully release the train before restarting other wise some danger to the train has to be faced. Therefore,the administration has adopted Twin pipe air brake system on the railways.The train examination staff must ensure that all trains examined by them are
invariably having Twin pipe air brake system .In case a train terminates at their station with single pipe system they must thoroughly check and investigate the reasons for single pipe system and ensure necessary repairs to put the defective coach/wagon back to Twin pipe system.
TYPES OF AIR BRAKES There are two types of air brakes which are present, they are, 1.Direct release system 2.Graduated release system
Direct releas releasee sys system tem::- In this system when after application of brakes,the brakes are released,the air of the brake cylinder does not quickly go to the atmosphere through the distributor valve .Instead it goes slowly.The Distributor valve is not provided with such a feauture which may permit the air of brake cylinder to escape quickly and release the piston quickly .Second or subsequent application of brake is not possible until and unless the brake cylinder air is completely exhausted .It is not possible for the distributor valve to make the releasing movement of piston to abruptly change to applying position .As such the application and release of brakes in quick succession cannot be achieved at all.So this system is termed as Direct release system.
Graduated releas Graduated releasee sys system tem:-In :-In this system application and release of brakes in quick succession is feasible in any number of times .In this system the movement of piston from application application to release release and vice versa can be changed with decrease decrease and increase increase of air pressure in B.P.In B.P.In this case there is no need for completely discharging the air pressure of brake cylinder.The distributor valve fitted in this type ,has the special feature which actuates the brake cylinder piston with the decrease and increase in B.P ,pressure to the tune of 0.5 kg/cm^2 or above. At the time of speed restrictions or while negotiating down gradients it has become very easy eas y to control the speed of the train to the will of driver.It is due to this reason that this system is called Graduated release system..
From the above ,one can easily understand that the type of air brake system in use on our railway system is Twin Twin pipe graduated release air brake system .But we call it only air brake system in short which has the same meaning and nothing else as in the case of vacuum where partial vacuum is used but termed as vacuum only. only.
PRINCIPLE OF OPERATION PRINCIPLE OPERATION OF TWIN PIPE GRADU GRADUA ATED RELEA RELEASE SE AIR BRAKE SYSTEM: SYSTEM :
a.
Charging the brake system
. . . .
Brake pipe throughout the length of train is charged with compressed air at 5 Kg/c m2 Feed pipe throughout the length of train is charged with compressed air at 6 Kg/cm2 Control reservoir is charged to 5 Kg/cm2 Auxiliary reservoir is charged to 5 Kg/cm2
b.
Brake application stage
For brake application the brake pipe pressure is dropped by venting air from the . driver’s brake vale. Subsequently the following action take place. . The control reservoir is disconnected from the brake pipe. The distributor distributor valve connects connects the auxiliary reservoir reservoir to the brake piston piston is pushed . outwards for application of brakes. . The auxiliary reservoir is however continuously charged from feed pipe at 6 Kg/cm2 Description Minimum Brake Application Service Brake Application Full Service Brake Application
Reduction in B. P. Pressure 0.5 to 0.8 Kg/cm2 1.0 to 1.0 Kg/cm2 Brake pipe is fully exhausted and its pressure reduces to almost zero.
c. Brake release stage Brakes are released by recharging brake pipes to 5 Kg/cm2 pressure through the . driver’s brake valve. . The distributor valve isolates the brake cylinder from the a uxiliary reservoirs. The brake cylinder pressure is vented to atmosphere through DV and the Brake . cylinder piston moves inwards.
Coaches fitted with twin pipe graduated release air brake system with locomotive in the leading forms a complete rake.Locomotive is the source for supplying compressed air to the trailing coaches in the rake.The brake pipe and feed pipe run parallel to eachother throughout the length of the coach.The brake pipe and feed pipe of one coach are connected to the brake and feed pipe of adjacent coaches through cut off angle cocks and hose coupling. The air compresser compresser of the locomotive locomotive stores the air in its main reservoir reservoir at a pressure pressure of 8-10 kg/cm^2 and it is supplied to the system charging the feed pipes and brake pipes com commonly called as FP and BP at a pressure of 6kg/ kg/cm^ cm^2 and and 5kg/ kg/cm^ cm^2 respectively.Auxiliary reservoir is charged by the feed pipe through the check valve and isolat isolating ing cock. cock. The auxilia auxiliary ry reserv reservoir oir is also also charg charged ed by the brake pipe pipe through through distributor valve in case the feed pipe is unable to charge, or has been eliminated. For continuity of air pressure through out the rake ,the cut off angle cocks of the brake and the feed pipe and isolating cocks should be kept open. The cut off angle cocks on the
last coach of the rake and front cut off angle cocks of the locomotive should be kept closed. Reduction of air pressure in the brake pipe whether intentionally or accident accidental al actuat actuates es the distri distribut butor or valve valve which which causes causes rise rise of pressu pressure re in the brake brake cylinder and the brake apply .The magnitude of braking force increases in proportion to the reduction of air pressure pressure in the brake pipe. Maximum Maximum braking force is attained attained when the brake pipe pressure is lowered and is in the range of 3.4 to 3.6kg/cm^2.In case of emergency(or accidents)the air pressure in brake pipe is reduced below from 3.4kg/cm^2 to hasten the brake application ap plication at a faster rate reducing the emergency braking distances. During application of brakes the air from auxiliary reservoir flows to the brake cylinder and the loss of air in auxiliary reservoir is made up by feed pipe continuously. The thrust of brake cylinder piston is transmitted through brake riggings magnifying the same through leverage to the brake blocks thereby producing braking force. The distributor valve is so sensitive that when air pressure is lowered or raised in the brake pipe it causes the brake application and release respectively. With the rise in air pressure it releases the brake cylinder by venting its air to the atmosphere and with the fall in the air pressure it applies brakes. Distributor valve which is fitted on the branch line of the brake pipe, controls all the activities related to the charging, application and release of the brake. (1)CHARGING :-Brake pipe is charged with air pressure at 5 kg/cm^2 through out the length of the rake and fills air in the distributor valve and control reservoir through dirt collectors. Feed pipe is charged with 6 kg/cm^2 through out the length of the rake and fills air in auxiliary reservoir through dirt collector and check valve with choke(Auxiliary reservoir is also charged by the brake pipe through the distribution valve). (2)APPLICATION :-In twin pipe graduated release system the driver of the train can apply brakes either in steps for graduated application or in one stroke for emergency application .This action causes reduction in brake pipe pressure due to its venting to atmosphere. The reduction in brake pipe pressure results in differential pressure building up across across the diaphr diaphragm agmss of the distri distribut butor or valve valve .As a result result the distri distribut butor or valve valve connects the auxiliary reservoir to the brake cylinder causing the brake cylinder piston to come out .The piston movement causes brake application on individual coaches through the brake rigging arrangement. (3)RELEASE :-For releasing the train brakes the driver has to replenish the brake pipe pressure reduced during brake application by charging the system back to 5 kg/cm^2.The increas increased ed press pressure ure is sensed sensed by the distri distribut bution ion valve valve which which discon disconnect nectss the brake brake cylinder from the auxiliary reservoir and connects the brake cylinder to atmosphere through the distributor valve.The brake cylinder pressure is vented to atmosphere and brakes are released. To ensure service reliability of the air brake system of the coaches preventive periodic maintenance is carried out.The following maintenance schedules are carried out on the coaches. Schedule-A (Monthly examination) Schedule -B(Tri-monthly examination) Schedule-C(Half yearly examination) To ensure that the air brake system of the different coaches of a rake work in conjunction reliable round trip examination is carried out.For service reliability of the coaches ,the coaches of a rake are subjected subjected to a periodic overhaul overhaul once in twelve twelve months.Certain activities like inspection and testing of the air brake equipment of the coaches are carried out during POH.The air brake equipment of the coaches is to be completely dismantled and overhaul once in five years or on completion of 8 lakh kilometers which ever is earlier or when there is some specific trouble .When a coach
comes for overhauling it is necessary to check whether the air brake equipment requires complete dismantling and over hauling.However the slack adjuster is to be over hauled every POH.
AIR BRAKE SUB-ASSEMBLIE SUB-ASSEMBLIES S The various Air Brake sub-assemblies and components are: i) Common pipe bracket. ii) Intermediate piece. iii) Brake pi pipe an and fe feed pi pipe. iv) Brake pipe coupling. v) Cut-off angle cock. vi) Brake cylinder. vii) Dirt collector. viii viii)) Auxi Auxili liar ary y rese reserrvoir voir.. ix) Slack adjuster. x) Distributor va valve. xi) Isolating cock. xii) PEASD. xiii) PEAV. xiv) Check valve.
COMMON PIPE BRACKET
Common pipe bracket is mounted on the coach under frame and is suitable for use with all type of distributor valves presently in use on main line coaches. INTERMEDIATE PIECE (SANDWICH PIECE)
An intermediate piece is mounted on the common pipe bracket to fit the distributor valve on the common pipe bracket. The intermediate piece serves the purpose of blanking all the other ports on the common pipe bracket other than required for a particular make of distributor valve. Each type of distributor valve is mounted on the common pipe bracket with its own intermediate piece.
BRAKE PIPE AND FEED PIPE
Brake pipe and feed pipe of 25 mm bore and branch pipes of 20 mm bore have been provided. BRAKE PIPE COUPLING
To maintain continuity through out the length of train, the brake pipe (BP) and feed pipe (FP) are fitted with flexible hoses. Each hose is provided with palm end coupling heads are painted with green colour for B.P and white colour for F.P. F.P. also raised letters ‘BP’ and ‘FP’ are embossed on coupling heads representing Brake Pipe and Feed Pipe respectively. respectively. Hose couplings must be checked for leakage of air as per the test procedure given below
CUT OFF ANGLE COCK
One cut off angle cock has been provided on either end of brake pipe and feed pipe that is to say on every coach on wagon a complement of 4 angle cocks are provided.
The angle cocks used on feed pipes are painted white and those for brake pipes are given coating of paint green.The angle cocks are fitted with Teflon tape or paint white lead on the brake pipes and feed pipes and made air tight joints by tightening their rear adaptors fully.The top of the cock having handle is invariably kept facing upwards.The angle cocks are secured with under frame member with strong safety loop.So ,that the angle cock may not move to and fro and right or left in dynamic conditions.Angle cock has one front adaptor in which the nipple of the air hose coupling is screwed in with paint white lead or Teflon tape and made firm and air tight joint.The diameter of the rear adaptor of angle cock corresponds to the external diameter; of air pipes and the front adaptor’s diameter; matches with that of air hose nipple.Since there is difference in diameter;of air pipes used on wagons and coaches ,as such the angle cocks are not inter-changeable. The advantage of provision of cut off angle cocks on the brake and feed pipes is that after charging c harging of air pressure in the air brake system ,if any coach or wagon has to be detached from a train formation, discharging of air pressure from whole train is not necessitated.The angle cocks of affected wagon and adjacent wagons or coaches are closed and the wagon/coach can be detached without any loss of air pressure and after re-formation of load and coupling up of air hoses, the train can be started immediately and there will be saving of time for recharging and building of pressure to desired levels as in the case of vacuum brake system,as the air pressure in rest of the wagon/coaches remains unaltered.
BRAKE CYLINDER
On every every coach coach fitted fitted with air brake syste system m two brake cylind cylinders ers are provid provided ed for actuating the brake rigging for the application of release of brakes. During application of brakes the brake cylinder develops mechanical brake power by outward movement of its pisto piston n assembl assembly y after after receivi receiving ng air pressu pressure re from from Auxilia Auxiliary ry reserv reservoir oir throug through h the distributor valve. This is transmitted to the brake shoes through a combination of leaves. Durin During g rele releas asee acti action on of brak brakes es the the compr compres essi sion on spri spring ng prov provid ided ed of brake brakess the the compression spring provided in the brake cylinder brings back the rigging to its original position. The cylinder body is made out of sheet metal or cast iron and carries the mounting bracket, air inlet connection, ribs and flange.
DIRT COLLECTOR
Two three way dirt dirt collector are provided one each coach. One between brake pipe and DV and other in between feed pipe & auxiliary reservoir reservoir.. Dirt collector collector prevents prevents the entry of the dust and scale by centrifugal action followed by filtration arrangement in the distributor valve & auxiliary reservoir and other equipment in the system AUXILIARY RESERVOIR SALIENT FEATURES
The auxiliary reservoir is a cylindrical vessel made of sheet metal. On both the ends of the reserv reservoir oir,, flange flangess are provid provided ed for pipe pipe connect connection ions. s. One end of the auxili auxiliary ary reservoir is connected to the brake pipe through the distributor valve. Auxiliary reservoir is charged through through the feed pipe to a pressure of 6kg/sq cm. At the bottom of the
auxiliary reservoir, reservoir, a drain cock c ock is provided for draining out the condensate moisture. The auxiliary reservoir should be overhauled in every POH. SLACK ADJUSTER SALIENT FEATURES
Slack adjuster (also known as brake regulator) is a device provided in the brake rigging for automatic adjustment adjustment of clearance/sl clearance/slack ack between brake blocks and wheel. It is fitted fitted into the brake rigging as a part of mechanical pull rod. The slack adjuster is double acting and and rapi rapid d work workin ing g i.e. i.e. it quic quickl kly y adju adjust stss too too lar large or too too smal smalll clea cleara ranc ncee to a predetermin predetermined ed value known as ‘A’ ‘A’ dimension. dimension. The slack adjuster maintains maintains this ‘A’ ‘A’ dimension throughout its operation. The slack passenger coaches, it is composed of the following parts. . Adjuster spindle with screw thread of quick pitches (non self-locking). Tractioin unit containing adjuster nut, adjuster unit containing leader nut and barrel . etc. . Control rod with head.
The out standing features of slack adjuster IRSA-450 are: Fully Automatic i.e. once initially set, no manual adjustment is further necessary at any time during its operation. Double-Acting i.e. the brake shoe clearance is adjusted to its correct value both ways, either when it has become too large (owing to wear of the brake shoes and wheels) or when it has become too small (e.g. owing to renewal of worn out brake blocks). Rapid working i.e. correct brake shoe clearance is automatically restored after one or two applications of the brake. Verification i.e. if resistance occurs early in the brake application, caused by heavy brake rigging, e.g. an ice coating on the brake shoes, etc., in such cases the slack adjuster does not pay out slack immediately, but indexes the amount of slack to be paid out. If the slack really is too small, the slack adjuster will pay out this indexed slack at the next brake application. Thus false payout will not occur. True Slack Sl ack Adjuster i.e. the slack adjusters incorrect slack only, thus giving the brake its best possible pre-adjusted limit of piston strokes, ensuring a smooth and efficient braking force at all times. Shock Resistant Resistant i.e. train shocks will not cause false take-up or payout of slack. When brakes are released, the moving parts of the slack adjuster are securely locked. ISOLATING COCK
One isolating cock ball type is provided near each brake cyulidner on the branch pipe line connecting brake cylinder and distributor valve. One isolating cock ball type is also provided on the branch pipe connecting brake pipe and passenger emergency valve. These isolatin isolating g cocks are used to isolate isolate the air passage passage in case the brake brake
cylinder / passenger emergency valve becomes defective. One isolating cock is also provided between centrifugal dirt collector of FP FP and check valve. The same may be isolated in the case of malfunction of DV or any breakage / damage in the branch pipes of the feed pipe. TESTING
1.
Hand Handle le “ OFF OFF “ pos posit itio ion n – Chec Check k leak leakag agee at out outle lett port port at air air pres pressu sure re 10 10 2 kg / cm . There should not be any leakage.
2.
Clos Closee the the out outlet let por port usin using g a blan blank k plat platee and and chec check k leak leakag agee all all over over the the 2 body at air pressure 10 kg / cm . There should not be any leakage.
3. PASSENGER EMERGENCY ALARM SIGNAL DEVICE (PEASD) Two such valves valves are fitted fitted at can rail rail level, level, on one end wall of the coach. coach. The operating spindle of the passenger emergency alarm signal equipment is connected to the disc disc rod and alarm disc disc rod is in turn connect connected ed to the alarm chain. chain. These These equipment are connected to passenger emergency valve by a common pipe of 10 mm bore. The PEASD can be reset with the square key kept with guard / TXR of the train. On all new coaches the PEASD has fixed reset key. key. TESTING
1. Hold the PEASD PEASD suitably suitably with with a pulling pulling handle handle attached attached to operati operating ng spindle. spindle. 2 Connect air supply of 5 kg / cm to port A and port B dummied suitably. 2. With ith the the lever lever assemb assembly ly at the the bott bottom om positi position on chec check k for for leak leakage age at the the exhaust exhaust port port and body all over over with soap suds. suds. There There should should not be any leakage. 3. With air supply supply on on operate operate the device device by pulling pulling down the handle handle and note note heavy blow of air through the exhaust port. 4. Quickly rest the the device by using the the suitable suitable spring spring key and and rotating rotating the lever lever assembly clock-wise and note the exhaust of air stops completely.
PASSENGER EMERGE EMERGENCY NCY VALVE VALVE (PEAV) (PEAV) This equipment equipment is fitted fitted on the end wall. It is connected connected to the brake pipe through isolating cock and is also connected to the passenger passenger alarm signal device. During the operation of the alarm chain from inside the compartment, the disc rod rotates and lifts the operating spindle of the passenger alarm signal device and in this process the air in the pipe between passenger alarm signal device and PEAV is depleted. The difference in the air pressure actuates the PEAV and the brake pipe pressure gets depleted to the atmosphere through PEAV exhaust having a choke of 4 mm dia. Depletion of brake pipe will initiate a brake application. PEAV PEAV also contains a micro – switch which is utilised utilised to provide an audio – visual indication indication to the driver of the train. The driver also gets the indication of alarm chain operation through increase in the requirement of air in flow meter. TESTING
1. Connect one one end of 110 110 cu. In. volume volume reservoir reservoir to to the BP Control Control Air Air Port of of the Relay Valve. The other end end of the reservoir reservoir to a ½” drain cock via a 2 pressure gauge. Also connect 5 kg / cm compressed air supply to BP inlet to the relay valve. Remove the choke from the exhaust passage of the valve.
2. With ith the ½” drai drain n cock cock close closed, d, open open the the 5 kg / cm2 air supply to the relay valve. Note that the pressure gauge of the reservoir quickly register register 5 kg / cm2 pressure and no leakage in the exhaust port. 3. Apply soap soap suds all over over body. body. No leakage leakage is permis permissible sible.. 4. Open the ½” ½” drain cock and note note the reserv reservoir oir pressur pressuree quickly drops to to zero, and at the same time the relay valve starts exhausting the BP. BP. 5. Close the the drain drain cock and note as the reservoir reservoir pressure pressure builds builds up and tends tends to equalise with the supply pressure, the relay stops exhausting. 6. At close close of test and before before insta installa llatio tion n of the relay valve valve on to the coach coach for back the choke on the exhaust passage.
CHECK VALVE WITH CHOKE
One such set is provided in the branch pipe connecting FP & AR. It ensures supply of compressed air from feed pipe to auxiliary reservoir and prevents its return flow, thus avoiding fall in air pressure below 5 kg/cm2 in the event of failure on air supply from feed pipe. A 3 mm dia choke is provided provided on the outlet outlet port of the check valve valve to control the quantum of air flow from feed pipe, so that the auxiliary reservoirs on all the coaches of a train can be uniformly filled. TESTING:
1.
Connect air supply at 10 kg / cm2 to the inlet port air should flow freely through the outlet port.
2.
Block out outlet po port and and per permit air air at 10 10 kg / cm cm2 through the inlet port. Check Check for leakage leakage all over the body and joints joints by soap water water. There There should not be any leakage.
3.
Connect air supply at 2 kg / cm2 to the outlet port. There should be no air flow / leak through the inlet port. p ort. Repeat the test at air pressure 5 kg / cm2.
Working principle Air Brake System (Passenger Rake) The Brake pipe and feed pipe run parallel parallel to each other through through out the length of the coach. The brake pipe and the feed pipe of one coach are connected to the brake pipe and feed pipe of adjacent coaches. Through cut off angle cocks and hose-couplings Air compressor located in the locomotive supplies air pressure at 5 kg/cm2 to the brake pipe through the drivers’s brake value The air compressor also supplies air at 6 kg.cm2 through a series of values to the feed pipe For continuity of air pressure through out the rake , the cut-off angle cocks of the brake and the feed pipe and isolating cocks should be kept open. The cit-off angle cocks on the last coach of the rake and front cut-off angle cocks of the locomotive should be kept closed
Working Principle Air Brake System (Passenger Rake) Distributor Value which is fitted on the branch line of the brake pipe Controls all the activities related to the charging , application and release of the brake 1. Charg Charging ing : Brake Brake pipe is charged charged with with air pressur pressuree at 5 kg/cm2 kg/cm2 throu through gh out the length of the rake and fills air in the distributor value and control reservoir through dirt collectors . Feed pipe is charged with 6 kg/cm2 through out the
length of the rake and fills air in auxiliary reservoirs through dirt collectors and check value with choke (auxiliary reservoir is also charged by the brake pipe through the distributor value) 2. Applic Applicati ation on : In twin twin pipe gradu graduated ated rele release ase syste system m the drive driverr of the trai train n can apply apply brak brakes es eith either er in step stepss for for grad graduat uated ed appli applica cati tion on or in one one stro stroke ke for for emergency application . This action caused reduction in brake pipe pressure due
Working Principle Air Brake System(Passenger Rake) To its venting to atmosphere . The reduction in brake pipe pressure results in differential pressure building up across the disphragms of the distributor value As a result the dis tributor value connects the auxiliary reservoir to the brake Cylinders causing the brake cylinder piston to come out . The piston movement causes barke application on individual coaches through the barje rigging 3. Release : For releasin releasing g the train brakes brakes the driver has has to replenish replenish the brake pipe pressure reducted during brake applicatons by charging the system back to 5 kg/cm2 . The increased pressure in sensed by the distributor value which disconnects the brakes cylinders from the auxiliary reservoir and connects the brake cylinder to atmosphere through the distributor value . The brake cylinder pressure is vented to atmosphere and brakes are released
Function Air Brake System (Passenger Rake) Coaches fitted with twin pipe graduated release air brake system with locomotive in the leading forms a complete rake. Locomotive is the source for supplying compressed air to the trailing coaches in the rake The brake pipe of coaches is charged with compressed air through the drivers brake value and the fed-pipe of the coaches is charged through the main reservoir of the locomotive via additional relay value The brake pipe and the feed pipe of the coaches in the rake are connected to the subsequent coaches through hose couplings for compressed air to flow for operating the braje system are fitted in the under frame These equipments and their functions are discussed in details separately Passenger emergency alarm system is provided in the coaches for passengers initiation of train brakes in the event of emergency safety
Maintenance Air Brake System (Passenger Rake) To ensure service reliability of the air brake system of the coaches preventive periodic maintenance on the coaches are carried out The following Maintenance schedule are carried out on the coaches Schedule –A (Monthly Examination) Schedule-B(Tri-Monthly Schedule-B(Tri-Monthly Examination) Schedule-C (Half Yearly Examination) The above maintenance schedule being pertinent to maintenance of coaches are discussed in detail in the section of maintenance of Air Brake System ( Passenger Coaches ). To ensure that the air brake system of the different coaches of a rake work in conjunction reliably round trip examination is carried out
Over Hauling Air Brake System (Passenger Rake ) To ensure service reliability of the coaches the coaches of a rake are subjected to a periodic overhaul once in twelve months . Certain activities like inspection and testing of the the ar brak brakee equi equipm pmen entt of the the coac coaches hes are are carr carrie ied d out during during POH POH The The air air brak brakee equipment of the coaches is to be completely dismantled and overhaul once is five years or on completion of 8 lakh kilometers which ever is earlier or when there is some specific trouble When a coach comes for overhauling it is necessary to check whether the air brake equipment requires requires complete complete dismantlin dismantling g and overhauling of individual individual of the air brake system see the respective section of overhauling of the component
Introduction
Fast expanding industrialization of country needs fast movement of higher freight and pas passe seng nger er traf traffi ficc coup couple led d with with safet afety y of men men and and mate materi rial al.h .hen ence ce the the rail railwa way y adminis administra tratio tion n took took the challen challenge ge and introd introduced uced highly highly effic efficien ientt and reliab reliable le AIR BRAKE SYSTEM over than vacuum brake system. Thus conventional vacuum brake system on these stock has been replaced which has several limitations as under:1.Brake fade. 2.Increased timings for release after application. 3.Limitations on train loads and lengths .Amount of vacuum in the rear portion po rtion is not maintained as desired
4.Higher maintenance costs 5.Speed.limitations 6.Lesser braking force generation by the piston 7.Difficult to create adequate amount of vacuum on Ghat sections 8.Upgrading of brake power before entry to ghat sections Whereas the AIR BRAKE SYSTEM has the following major advantages over the vacuum brake system:1.Speed of trains are increased 2.Axle load of wagon has been increased 3.Increased freight per train 4.Shorter braking distances 5.Compact and easy to maintain resulting in better utilization of rolling stock 6.Availability 6.Availability of optimum and uniform brake power enab ling handling heavier trains, needing no augmentation before entering ghat section 7.Better reliability and safety 8.Higher pay load due to its being lighter in weight 9.Inexhaustibility
AIR BRAKE SYSTEM
For application of brakes in railway coaches and wagons with vacuum brake system we firs firstt with withdr draw aw air air from from the the trai train n syst system em(c (cre reat atee vacu vacuum) um) and and then then allo allow w the the atmospheric air to reach below the piston in vacuum cylinder lifting the piston upwards which in turn apply brakes.But in air brake system it is the reverse case.In air brake system we first charge the train system with compressed air to certain predetermined level of air pressure through two pipes named feed pipes and brake pipes.The feed and brake pipes are charged to a pressure of 6.0 and 5.0 kg/cm^2 respectively.When brakes are to be applied the air pressure in brake pipe is reduced by the driver which actuates the distributor valve fitted under every wagon or coach on the train .The distributor valve supplies the compressed air from auxiliary reservoir to one side of the piston in the brake cylinder pushing out the piston rod and applying the brakes.The guard and the passengers can also apply the brakes in case of an emergency .During train partings and accidents brakes also apply automatically and with higher force than that of vacuum brakes.When the air pressure in brake pipe is restored to the normal pressure,the brakes are released. The brakes can also be manually released after the engine has been detached.After application of brakes in air brake system the brakes remain in on position for hours together. Only those engines which are fitted with the air brake system can only work such trains.Such wagons/coaches can also not be worked with other trains with vacuum brake system TWIN PIPE SYSTEM:-As SYSTEM:-As already stated above each and every brake system has two air pipes pipes from from one end end to the the othe otherr end end lengt lengthw hwis ise.O e.One ne pipe pipe is used used to cont contin inuo uosl sly y charge/feed the compressed air to the auxiliary reservoir and is called as Feed pipe.The second pipe is used for application and releasing of brakes and is termed as Brake pipe.As such this system is called as Twin pipe system.This system has the following merits:Feed pipe charges charges the Auxiliary Auxiliary reservoir continuosly continuosly and maintains maintains the predetermin predetermined ed air pressure pressure in A.R(Auxiliary A.R(Auxiliary reservoir).On reservoir).On application application of brakes the
A.R’S compressed air is fed to the brake cylinder and there is a certain fall in air pressure in A.R due to the same.But the feed pipe immediately/simultaneously charges the A.R and maintains the desired air pressure in A.R.Any number of brake applications releasing may be done by the driver in quick succession, the air pressure in A.R will remain the same i.e; there will be no decrease in the air pressure of A.R. This feature is not possible in case feed pipe is removed/isolated from the Air brake system,because the brake pipe will have to shoulder the burden of feed pipe in addition to his own job.In such an event the charging of A.R will take more time to be ready for subsequent brake applications.Resultantly the application of brakes in quick succession is not possible. In case due to any reason one pipe of a coach or any wagon gets damaged or goes defective,it can be bypassed in twin pipe system and the detachment of the coach or wagon would not be essential as in the case of single pipe system,But in this case the train will be worked as single pipe system. SINGLE PIPE SYSTEM:-In this system there is provision of only one air pipe from one end of a wagon/coach to the other end instead of two pipes.This pipe is called as brake pipe.This brake pipe singularly charges the auxiliary reservoir and also applies and releases the brakes.In this system the driver feels very easy in maintaining/charging the brake pipe only but this is not so advantageous to that of Twin pipe system.In this system the auxiliary reservoir is not charged while the A.R supplies air to brake cylinder.As such brakes in quick succession cannot be applied and released.In case of any damage or defect in the air brake system of any coach/wagon,there is no alternative than to detach such coach/wagon coach/wagon from train train enroute.In enroute.In this system system after emergency emergency application application of brakes the driver shall have to wait for some time to fully release the train before restarting other wise some danger to the train has to be faced. Therefore,the administration has adopted Twin pipe air brake system on the railways.The train examination staff must ensure that all trains examined by them are invariably having Twin pipe air brake system .In case a train terminates at their station with single pipe system they must thoroughly check and investigate the reasons for single pipe system and ensure necessary repairs to put the defective coach/wagon back to Twin pipe system. TYPES OF AIR BRAKES
There are two types of air brakes which are present, they are, 1.Direct release system 2.Graduated release system Direct release release system:system:- In this system system when after application application of brakes,the brakes,the brakes are released,the air of the brake cylinder does not quickly go to the atmosphere through the distributor valve .Instead it goes slowly.The Distributor valve is not provided with such a feauture which may permit the air of brake cylinder to escape quickly and release the piston quickly .Second or subsequent application of brake is not possible until and unless the brake cylinder air is completely exhausted .It is not possible for the distributor valve to make the releasing movement of piston to abruptly change to applying position .As such the application and release of brakes in quick succession cannot be achieved at all.So this system is termed as Direct release system.
Graduated release system:-In this system application and release of brakes in quick succession is feasible in any number of times .In this system the movement of piston from application application to release release and vice versa can be changed with decrease decrease and increase increase of air pressure in B.P.In B.P.In this case there is no need for completely discharging the air pressure of brake cylinder.The distributor valve fitted in this type ,has the special feature which actuates the brake cylinder piston with the decrease and increase in B.P ,pressure to the tune of 0.5 kg/cm^2 or above. At the time of speed restrictions or while negotiating down gradients it has become very easy eas y to control the speed of the train to the will of driver.It is due to this reason that this system is called Graduated release system.. From the above ,one can easily understand that the type of air brake system in use on our railway system is Twin pipe graduated release air brake system .But we call it only air brake system in short which has the same meaning and nothing else as in the case of vacuum where partial vacuum is used but termed as vacuum only. only.
AIR BRAKE SYSTEM
INTRODUCTION:
In Air Brake system compressed air is used for operating the brake system. The locomotive compressor charges the feed pipe and the brake pipes throughout the legth of the train. The feed pipe is connected to the brake cylinder through the distributor valve. Brake application takes place by dropping the pressure in the brake pipe. PRINCIPLE PRINCIPLE OF OPERATION OPERATION OF TWIN PIPE GRADUA GRADUATED RELEASE RELEASE AIR BRAKE SYSTEM: a.
Charging the brake system
. . . .
Brake pipe throughout the length of train is charged with compressed air at 5 Kg/c m2 Feed pipe throughout the length of train is charged with compressed air at 6 Kg/cm2 Control reservoir is charged to 5 Kg/cm2 Auxiliary reservoir is charged to 5 Kg/cm2
b.
Brake application stage
. For brake application the brake pipe pressure is dropped by venting air from the driver’s brake vale. Subsequently the following action take place. The control reservoir is disconnected from the brake pipe. . . The distributor distributor valve connects connects the auxiliary reservoir reservoir to the brake piston piston is pushed outwards for application of brakes. The auxiliary reservoir is however continuously charged from feed pipe at 6 Kg/cm2 . Description
Reduction in B. P. Pressure
Minimum Brake Application Service Brake Application Full Service Brake Application
0.5 to 0.8 Kg/cm2 1.0 to 1.0 Kg/cm2 Brake pipe is fully exhausted and its pressure reduces to almost zero.
c. Brake release stage Brakes are released by recharging brake pipes to 5 Kg/cm2 pressure through the . driver’s brake valve. . The distributor valve isolates the brake cylinder from the a uxiliary reservoirs. The brake cylinder pressure is vented to atmosphere through DV and the Brake . cylinder piston moves inwards.
AIR BRAKE SUB-ASSEMBLIES
The various Air Brake sub-assemblies and components are: xv) Common pipe bracket. xvi) vi) Intermedia diate pi piece. xvii xvii)) Brak Brakee pip pipee and and feed feed pipe pipe.. xviii xviii)) Brak Brakee pip pipee coup coupli ling. ng. xix) Cutut-off angl ngle cock ock. xx) Brake cy cylinder. xxi) Dirt co collector. xxii xxii)) Auxi Auxili liar ary y res reser ervo voir ir.. xxiii xxiii)) Slac Slack k adjus adjuster ter.. xxiv xxiv)) Dist Distri ribu buto torr valve valve.. xxv) xv) Isolating cock ock. xxvi) PEASD. xxvii xxvii)) PEA PEAV. xxviii) xxviii) Check Check valve. valve. The brief details of the air brake components and it’s maintenance and test procedure is described below: COMMON PIPE BRAKET
Common pipe bracket is mounted on the coach under frame and is suitable for use with all type of distributor valves presently in use on main line coaches. INTERMEDIATE PIECE (SANDWICH PIECE)
An intermediate piece is mounted on the common pipe bracket to fit the distributor valve on the common pipe bracket. The intermediate piece serves the purpose of blanking all the other ports on the common pipe bracket other than required for a particular make of distributor valve. Each type of distributor valve is mounted on the common pipe bracket with its own intermediate piece. AIR BRAKE HOSES Brake Pipe and Feed Pipe Hoses
To maintain continuity through out the length of train, the brake pipe (BP) and feed pipe (FP) are fitted with flexible hoses. Each hose is provided with palm end coupling heads are painted with green colour for B.P and white colour for F.P. F.P. also raised letters ‘BP’ and ‘FP’ are embossed on coupling heads representing Brake Pipe and Feed Pipe respectively. respectively. Hose couplings must be checked for leakage of air as per the test procedure given below
CUT OFF ANGLE COCK
Cut off angle cocks are provided both on brake pipe and feed pipe on either end of each coach to facilitate coupling and uncoupling of air hoses. Testing and Cut Off Angle Cock Tools and Equipment . . .
. . .
Test Bench Compressor to build pressure up to 10 kg/cm2. Single ended spanner as per IS 2027 a) Acro Across ss face face 17 17 (for (for M10 M10 lock lock nut nut)) 1No. 1No. b) b) Acro Across ss fac facee 13 (for (for M8 M8 STUD STUDS) S) 2No 2No.. Screw Driver –300mm, 1 No. 1 ¼ “ BSP dummy Plug with seal. Dummy plug for angle cock.
BRAKE CYLINDER
On every every coach coach fitted fitted with air brake syste system m two brake cylind cylinders ers are provid provided ed for actuating the brake rigging for the application of release of brakes. During application of brakes the brake cylinder develops mechanical brake power by outward movement of its pisto piston n assembl assembly y after after receivi receiving ng air pressu pressure re from from Auxilia Auxiliary ry reserv reservoir oir throug through h the distributor valve. This is transmitted to the brake shoes through a combination of leaves. Durin During g rele releas asee acti action on of brak brakes es the the compr compres essi sion on spri spring ng prov provid ided ed of brake brakess the the compression spring provided in the brake cylinder brings back the rigging to its original position. The cylinder body is made out of sheet metal or cast iron and carries the mounting bracket, air inlet connection, ribs and flange. Tools and Equipments Serial No.
1. 2. 3. 4. 5. 6. 7.
Description
Torque Wrench 0-3 Kg m range. Double End Spanner 24x27 mm across face (for M16). Double End Spanner across face 13x 14 (for M12). Socket Wrench 19 mm (for M12). Screw Driver 12” (300). Special fixture (Screw press/ Pucumatic). Gauge for examining bore of the cylinder. cylinder.
Inspection and Repairs of the Parts . Examine visually that the internal surface is free from scratches, rust. . Brake cylinder bore to be checked for ovality with gauge. Check the characteristics of the return spring. . . Piston trunk to be checked for wear and tear. . Pin, piston rod should be checked check ed for wear. Dome cover shall be checked for excessive wear and if worn build up with welding . and thereafter re-bore to required size. . Gange, bush bore of the piston rod, replace it if worn.
Testing of Brake Cylinder Body for Leakage
Before assembly, put dummy plate on the dome side and subject the brake cylinder for hydraulic pressure of 10 Kg/cm2 for 5 minutes. No leakage is permitted. Testing of Brake Cylinder i)
Brake Cylinder Test Bench
Test bench consists of the following main parts pa rts a) 5 nos. nos. of isolat isolating ing cocks cocks (1a, (1a, 1b,1c, 1b,1c,1d, 1d,1e 1e and and 1f). 1f). b) b) Pres Pressu sure re red reduci ucing ng valv valves es as bel below ow c) 2a –to –to be be set set on 10 Kg/c Kg/cm2 m2.. d) 2b –to –to be be set set on 6 Kg/ Kg/cm cm2. 2. e) 2c –to –to be be set set on 0.8 0.8 Kg/ Kg/cm cm2. 2. f) 2d –to –to be be set set on 3.8 3.8 Kg/ Kg/cm cm2. 2. g) Pres ressur sure gau gauge gess. h) 6a –to –to mea measu sure re sup supply ply pres pressu sure re.. i) 6b –to –to mea measu sure re bra brake ke cyli cylinde nderr pres pressu sure re.. j) j) Pipe Pipe line line filt filter er –Ite –Item m no no 3. 3. k) Brake cylinder cylinder pressure pressure mounti mounting ng base base with with fixture fixture –Item no4. l) Air Air rese reserv rvoi oirr –It –Item em no.5 no.5.. AUXILIARY RESERVOIR SALIENT FEATURES
The auxiliary reservoir is a cylindrical vessel made of sheet metal. On both the ends of the reserv reservoir oir,, flange flangess are provid provided ed for pipe pipe connect connection ions. s. One end of the auxili auxiliary ary reservoir is connected to the brake pipe through the distributor valve. Auxiliary reservoir is charged through through the feed pipe to a pressure of 6kg/sq cm. At the bottom of the auxiliary reservoir, reservoir, a drain cock c ock is provided for draining out the condensate moisture. The auxiliary reservoir should be overhauled in every POH. SLACK ADJUSTER SALIENT FEATURES
Slack adjuster (also known as brake regulator) is a device provided in the brake rigging for automatic adjustment adjustment of clearance/sl clearance/slack ack between brake blocks and wheel. It is fitted fitted into the brake rigging as a part of mechanical pull rod. The slack adjuster is double acting and and rapi rapid d work workin ing g i.e. i.e. it quic quickl kly y adju adjust stss too too lar large or too too smal smalll clea cleara ranc ncee to a predetermin predetermined ed value known as ‘A’ ‘A’ dimension. dimension. The slack adjuster maintains maintains this ‘A’ ‘A’ dimension throughout its operation. The slack passenger coaches, it is composed of the following parts. Adjuster spindle with screw thread of quick pitches (non self-locking). . . Tractioin unit containing adjuster nut, adjuster unit containing leader nut and barrel etc. Control rod with head. . The out standing features of slack adjuster IRSA-450 are: Fully Automatic i.e. once initially set, no manual adjustment is further necessary at any time during its operation. Double-Acting i.e. the brake shoe clearance is adjusted to its correct value both ways, either when it has become too large (owing to wear of the brake shoes and wheels) or when it has become too small (e.g. owing to renewal of worn out brake blocks). Rapid working i.e. correct brake shoe clearance is automatically restored after one or two applications of the brake. Verification i.e. if resistance occurs early in the brake application, caused by heavy brake rigging, e.g. an ice coating on the brake shoes, etc., in such cases the slack adjuster does not pay out slack immediately, but indexes the amount of slack to be paid out. If the slack really is too small, the slack adjuster will pay out this indexed slack at the next brake application. Thus false payout will not occur. True Slack Sl ack Adjuster i.e. the slack adjusters incorrect slack only, thus giving the brake its best possible pre-adjusted limit of piston strokes, ensuring a smooth and efficient braking force at all times. Shock Resistant Resistant i.e. train shocks will not cause false take-up or payout of slack. When brakes are released, the moving parts of the slack adjuster are securely locked.
CARRIAGE REPAIR WORKSHOP LALLAGUDA, SECUNDERABAD – 500 017
1. INTRODUCTION:
South Central Railway, Carriage Repair Workshop, Lallaguda, Secunderabad, a premier repair repair worksh workshop op of Indian Indian Railwa Railways ys was establis established hed on 30th September September 1893. This workshop was under the argis of “THE NIZAM GUARANTEED STATE RAILWAYS” for undertaking periodic overhauling and repairs to BE and MG steam locomotives,
coaches and wagons. Subsequently it was brought under the preview of “NIZAM STATE RAILW RAILWAYS.” Consequently upon the re-organization of Railways Railwa ys in 1951, this workshop became a integral part of Central Railways, subsequently South Central Railway was formed on 2nd October 1966 it became a major workshop for the zone. It continued to composite workshop for MG and BG rolling stock till 1969 when a repair to MG rolling stock was off loaded to Hubli workshop. With the tapering of Locos and bifurcation of wagons under wagon repair workshop at Guntapalli. Carriage workshop was exclusively meant for undertaking POH of carriages. This workshop occupies an area of 13.97 hectares with 4.25 hectares under cover. It is equipped and supported with full facilities within its premises. Carriage Rep air Workshop Workshop of Lallaguda is one of the few integrated workshops in Indian Railways. In the past decades the workshop carried out periodically overhauling of the BG main line coaches including A/C coaches and backup manufacturing activities like Brake blocks, repairs of springs, maintenance of BD steam cranes. Prime activities of this workshop workshop is periodical periodical overhauling of BG and A/C coaches and corrosion repairs to the coaches with allied activities of manufacturing of carriage components like brake gear items, equalizing stays etc, formation of rakes for express trains, conversion of GS coaches. The other activities carried out in this workshops are 1) Laboratory headed by CMT, 2) Basic Training Center for imparting technical education and implementation of Apprentice Act 1961, and 3) Computer center under supervision of Dy.CME / Sr. EDPM in order to modernize the working system had been a boon.
DISTRIBUTOR DISTRI BUTOR VALVE
Distributor valve is the most important functional component of the air brake system and is also sometimes referred to as the heart of the air brake system. The distributor valve senses drop and rise in brake pipe pressure for brake application and release respectively. It is conne connect cted ed to the the brak brakee pipe pipe thro throug ugh h bran branch ch pipe. pipe. Vario arious us other other compon componen ents ts connec connecte ted d to the the dist distri ribut butor or valv valvee are are auxi auxili liary ary rese reserv rvoir oir,, brak brakee cyli cylind nder erss and and reservoir.control Function of Distributor Valve
For application and release of brakes the brake pipe pressure has to be reduced and increased pipe pressure has to be reduced and increased respectively with the help of driver’s brake valve. During these operations the distributor valve mainly performs the following functions. (i) Charges the air brake system to regime pressure during normal running condition. (ii) Helps in graduated graduated brake application, application, when preaaure preaaure in brake pipe is reduced in steps. (iii) Helps in graduated brake release, when pressure in brake pipe is increased I steps. (iv) Quickly propagates reduction of pressure I brake pipe throughout the length of the train by arranging additional air pressure reduction locally inside the distributor valve. (v) Limits maximum brake cylinder pressure for full service application/emergency application. (vi) Controls Controls the time for brake application application and brake release release depending depending on service service conditions.
(vii) Facilitates complete discharge of air from the air brake system system manually with the help of operating ope rating lever. (viii) Protects overcharging of control reservoir reservoir when when the brake pipe pressure is quickly increased for releasing the brakes. Three designs of distributor valves are in use on coaches. These are: i) ii) iii)
C3W type distributor valve. KE type distributor valve. P4AG type distributor valve.
C3W DISTRIBUTOR VALVE
The C3W Distributor Valve Valve consists of. i. ii.
Main body Quick service valve
iii. iv. iv. v. vi. vii. viii. ix.
Main valve Limiting device Double release valve Auxiliary reservoir check vale Cut off valve Application chock Release chock
Operation of C3W Distributor Valve
For effective functioning of the air brake system, the distributor valve has to operate effectively during i) ii) iii)
Charging stage Application stage and Release stage
Charging Stage
During charging stage the compressed air flows from the brake pipe and enters into the brake pipe chamber of the main valve, cut off valve and quick service valve. Due to this pressure the various valves get, activated and perform as under. Main Valve: Due to brake pipe pressure acting on top face of the large diaphragm, diff differ erent entia iall pres pressu sure re acts acts on the the main main valv valve. e. As a resu result lt the the holl hollow ow stem stem moves moves downwards there by connecting brake cylinder to atmosphere.
In addition to this because of BP pressure at top of large diaphragm it presses ring and trigger. This action unlocks the CR release valve by raising upward the locking rod. Cut Off Valve: As brake pipe pressure enters into the cut off valve it flows through the solex jet and valve, (which is held open due to action of BP pressure on bottom side of the lower diaphragm) to the control reservoir. As the CR and BP pressure equalizes, diaphragm assembly come down and valve reach to lap position, the control reservoir pressure now also reaches to the upper portion of top diaphragm of quick service valve and the bottom portion of large diaphragm of main valve. Simultaneously, the auxiliary reservoir is charged with BP pressure reaching from cut off valve chamber – via auxiliary reservoir check valve. . EMERGENCY APPLICATION APPLICATION
During emergency application the brake pipe pressure is reduced rapidly to 0 kg/cm2 by the driver’s brake valve. Because of this drop the position of the various valves will be as described below. below. Main valve: With drop in BP pressure to 0 kg/cm2 differential pressure acts across the large diaphragm. As a result the hollow stem is moved in upward direction and pushes the chock valve there by opening the passage for entry of auxiliary reservoir pressure at top portion of main valve. This pressure then gets a way to brake cylinder thus gets a way to brake cylinder through limiting device. The brake cylinder thus gets charged with the compressed air. This pressure is known as BC-pressure.
Limiting Device: The auxiliary reservoir pressure which entered into the top position of main valve now enters the limiting device through the valve which is held open. From limiting device air pressure now enter the brake cylinder. When the BC pressure rises to 3.8 kg/cm2 the upwards force on the bottom of the guide and the valve at the bottom of the limiting device gets closed. Thus further entry of air into the brake cylinder stops.
When the brake cylinder cylinder pressure pressure reaches 3.8 kg/cm2 this pressure i.e. BC pressure act on . . .
Top face of small diaphragm of main valve. Bottom face of upper diaphragm of cut off valve. Top (small chamber) of quick service valve.
Now because of this BC pressure acting at main valve small diaphragm, the hollow stem is pulled down. As a result the check valve at top comes down to close stage and assume lap position with the hollow stem closing further entry of AR pressure. Cut off valve: In cut off valve the bottom face of the upper diaphragm is subjected to BC pressure because of which the guide is lifted. Also the upper portion of lower diaphragm is subjected to CR pressure, which pushes the total assembly downwards. This action closes the valve of cut off valve, there by isolating it from control reservoir pressure. Quick Service Valve: In quick service valve BC pressure acts at top of valve and control reservoir pressure act at top face of upper diaphragm. As a result the stem is pushed down. The valve at the bottom gets opened. Now as the BP pressure inside the DV is at 0 kg/cm2 the residue inside BP pressure from the bulb of quick service valve will flow back and vent to atmosphere with the BP line. GRADUATED APPLICATION
During graduated brake application the brake pipe pressure is dropped in steps by driver’s brake valve. The movement of various valve assemblies is almost in the same direction, but but thei theirr move moveme ment nt is compa compara rati tive vely ly less less.. In the the main main valv valvee howe howeve verr afte afterr each each application the hollow stem assumes the lap position with the check valve. In addition to this during graduated application the bottom valve of limiting device is held open to allow compressed air to enter into brake cylinder c ylinder.. When BC pressure reaches 3.8 kg/cm2 the bottom valve in the limiting device gets closed. Similarly at the time of full service ap plication as the BC pressure reaches reache s 3.8(+_) 0.1 kg/cm2 within specified time, the position of various valve assemblies will be the same as described above. iii) Release Stage When the brake pipe pressure is increased in steps steps for graduated release release of the different different valves is as described below: Main valve: At the top face of large diaphragm as the BP pressure increases, the hollow stem is moved downward leaving its lap position with check valve. The BC pressure thus
finds a passage from top of hollow stem to exhaust to the atmosphere. This action reduces pressure on top of the upper diaphragm and the hollow stem again lifts up to lap portion. It close the hollow stem top portion. The same cycle is repeated when BP is increased during next stages. In this way graduated release effect is obtained. Cut off valve: As the BP pressure increases the position of cut valve remains similar as in graduated application i.e. the cut off valve will remain closed, isolating CR pressure from brake pipe pressure.
When the BP pressure is increased then as explained above for Quick service valve: the main valve the BC pressure gets exhausted to atmosphere. This action gradually reduces the BC pressure. When BC pressure reduces the BC pressure. When BC pressure reduces to 0.8 kg/cm2 during brake release the force at the top of the quick service valve, becomes comparatively less than BP pressure present in Quick Service Valve. As a result the valve at top gets lifted thereby giving passage to blocked BP pressure to atmosphere. With the exhaust of BP pressure the Quick service valve of the distributor valve again ready for next brake application. Manual release: release: Double release valve provides provides for accelerated accelerated manual brake release, release, which is particularly useful during shunting operation. A short pull on the leaver of double release valve is all that is needed. This action opens the control reservoir release check valve, which is then held open by the locking rod. Venting of reservoir release check valve brings the main valve to release position and exhaust the brake cylinder pressure through the hollow stem. \
KE DISTRIBUTOR DISTRI BUTOR VALVE ALVE Operation of KE Distributor Valve
For effective functioning of the air brake system the KEGisl distributor valve has to operate effectively during Charging stage Application stage and Release stage. (i)
Charging Stage
During charging this stage the compressed air flows from the driver’s brake valve into the brake pipe which charges the control reservoir, bottom cover chamber and auxiliary reservoir. In twin pipe air brake system the auxiliary reservoir is also charged through the feed pipe from the rear end. Charging of control reservoir
During charging the compressed air flows from brake pipe, dirt collector, isolating valve and through choke to brake pipe chamber above ab ove the large piston and to the ‘A’ ‘A’ controller. controller.
Due to brake pipe pressure acting on top of the large piston, the three pressure valve is pushed down and port gets closed by the large diaphragm. Air also flows to the ‘A’ controller through chock. It passes through sensitivity port 2 and from there to the bottom cover chamber through port 2c. from the bottom cover chamber the air enters the control reservoir. reservoir. When the BP pressure above the large diaphragm gets equal to control reservoir pressure (at bottom cover chamber) the large piston diaphragm gets lifted up and opens port 2b. Charging of Auxiliary Reservoir
For charging the auxiliary reservoir air from BP passes from dirt collector to the ‘R’ charg charger er via via the the isol isolat atin ing g valve. valve. Air Air ente enteri ring ng the the ‘R’ ‘R’ char charge gerr pass passes es thro through ugh the the interm intermedi ediate ate piece piece and opens opens the sealin sealing g flap. flap. There There from from air enters enters the auxilia auxiliary ry reservoir and charges it to 5 kg/cm2. Simultaneously the auxiliary reservoir is charged by the feed pipe through dirt collector, isolating cock and check valve with chock to 6 kg/cm2 from the rear end. Application Stage : The application of brakes can either be emergency ,full service or graduated Emergency application When the brake pipe pressure is reduced from 5kg/cm2 to zero the passage from auxiliary reservoir to the brake pipe is closed by the sealing flap in the ‘R’ charger because of differenti differential al pressure pressure acting on either side side in the sealing flap at the same time pressure diferential acts across the large diaphragm of the three pressure value which pushes the piston unit (Large &Small (Upwards The upward movement of the piston unit closes the outlet port by uplifting of the control sleeve In addition to this outlet port at the top of the three pressure value closes and the inlet port opens . The air from auxiliary reservoir through the open inlet port the minimum pressure limiter the minimum pressure limiter enters the brake cyminders When the pressure in the brake cylinders reaches 0.8 kg/cm2 the minimum pressure limite limiterr gets gets closed closed and there there after maximum maximum pressure pressure limiter limiter gets gets closed closed when the pressure in the brake cylinders reaches 3.8 kg/cm2 with the rise in C pressure in the control reservoir During full brake application the brakes are applied at slower rate than in emergency application BP pressure to be reduced by 1.5 kg /cm2 instead of 5 kg/cm2 Note: At the beginning i.e. when BP is reduced and control sleeve uplifts outlet port –BP from top of the control sleeve reaches U.Chamber control open o atmosphere and some BP thus vent off this causes a sudden extra drop in the remaining BP pressure inside the DV and accelerates the effect of brake application propagating this action through out this action through out the length of the train By this brake cylinders pressure starts to rise. The brake cylinders pressure also acts on diaphra diaphragm gm at U- Contro Controlle llerr. A control controller ler minimu minimum m pressu pressure re limite limiterr and maximu maximum m pressure limiter. As BC start to rise the A controller value is closed isolated BP and CR .
Also the U controller value is closed and local reduction of BP is stopped As BC reaches 0.8kg. it clses the minimum pressure limiter and now the rising BC pressure can pass through maximum limiter through choke 16 which regulates the rate of BCrising As BC reaches 3.8+- 0.1 come to effect at BP drop 1.5 kg )
Graduated application (see figure) When the brake pipe pressure is reduced in steps for graduated application of brakes the the incrase I brake cylinder pressure is at a controlled rate and in proportion to brake pipe pressure reduction As soon soon as the brake cylind cylinder er pressu pressure re rises rises in propor proportio tion n to brake brake pipe pipe pressu pressure re reduction it causes the pistion unit (large &small) to move down into lap position thereby closing the top outlet port with out opening the top outlet port Thus feeding of air from the auxiliary reservoir to the brake cylinder is cut off this cycle is repeated every time BP is reduced in steps effecting graduated application of brakes iii) Release Stage For releasing the brakes when the pressure in the brake pipe is increased the pressure above the large large piston increases increases thus the differenti differential al pressure pressure across the large pisto pisto reduces as a result result the piston reduces reduces as a result the piston unit (Large&Sma (Large&Small) ll) loves down thereby opening the top inlet port The brake cylinder pressure thus passes through the outlet thorugh the release choke provided as the BP pressure reaches 4.85 kg/cm2 the brake cylinder is almost completely draines and the thre pressure assembly attains its charging / running position again Note: in twin pipe system system during succeeive succeeive application application and relase of brakes air flows flows from feed pipe to the auxialiary reservoir directly .Thus the brake pipe pressure feeds directly the three pressure value This result in faser rise of brake pipe Graduated Release If the pressure in the brake pipe is increased in steps the relasing procedure starts as before how ever the top outlet port get closed and come to lap position as soon as piston unit (Large & small) moves up due to fall to brake cylinder pressure
Pg 27- 29. .. . . . DESIGN & FABRICATION OF TEST STAND FOR SUB-ASSEMBLIES OF D.V’S . Distributive value consists of four major sub-Assemblies .They are: 1. Relay valu alue 2. Bottom cove over 3. Choke cove over 4. R-charger BOTTOM BOT TOM COVE C OVER R: This valve has been provided in the bottom of the D.V. below the main diaphragm only its release lever is visible from outside which has one or two holes with which the release release wires are tied and the other ends of the release wires are secured on sole bars on either side of the wagon for facilitating operation
TEST ACCESSORIES FOR BOTTOM BOT TOM COVER :1. Pressure regulator valve
1
2. Isolating cocks
2,4,5,6
3. Reservoirs (25L)
3
4. Reservoirs (6L)
8
5.Pressure gauge (0-10 kg/cm2)
9,10
8.Bottom cover mounting base
7
BOTTOM COVER
R-CHARGER:
The R-charger R-charger automatically automatically stops further further charging charging of AR when the air pressure pressure inside it reaches 5 kg/cm2 .the work has been derived by cut off valve in DV of stone India Grey sham & co. gets this job done through a choke
TEST ACCESSORIES ACCESSORIES FOR R-CHARGER:1. Pressure regulator
1
2. Isolating cocks
2,3,6
3. Reservoirs (3L)
7,8
4. Reservoirs (57L)
9
5.Isolating cock with choke 0.8 dia
4
6. Isolating cock with choke 6.0 dia
5
7.Pressure gauge (0-10 kg/cm2)
10,11,12
8.R-charger mounting base
13
R-CHARGER
CHOKE COVER:
-
‘A’ controller charger C.R with 5 kg/cm2 air pressure and simulates the ‘R’ charger to open the passage for the B.P air pressure to reach and charge A.R at the rate of 5 kg/cm2. simultaneously it protects the C.R from overcharging.
TEST ACCESSORIES ACCESSORIES FORCHOKE COVER: 1. Pressure regulator valve
1
2. Isolating cocks
2,4,5,6
3. Reservoirs (75L)
3
4. Reservoirs (10L)
7
5.Pressure gauge (0-10 kg/cm2)
9,10
8.Bottom cover mounting base
8
CHOKE COVER
RELAY VALVE:
In a Distributo Distributorr value of Passenger stock a single single -stage -stage relay value with a transmiss transmission ion ratio of 1.1 is used instead of side cover. KE distributor value equipped with a relay value has a univer universa sall actio action n .i.e. .i.e. the the brake brake cylin cylinder der volume volume.. This This means means that that the same same distributor value can be used different brake cylinder sizes and piston strokes with out requiring any special modification (change of ch ikes etc.) Working of Relay Value Introduction Relay Relay Value alue K.R.I K.R.I works works in conjunc conjunctio tion n with with the Distri Distribut butor or value value type type “KE “for “for Passenger stock Relay. Value which has a high feeding capacity has a universal action as already explained in the main features and maintain the application and release timings as specified in RDSO Specification No 02-ABR-94 of an ind ividual coach. Our principals in Germany who are the original designer of KE Distributor value recommends the use of Relay value with KE distributor value to achieve the application and release timings as per U.I.C specifications Release and running (See Sketch) During release and running position. Aux Reservoir pressure also acts on the top of the relay value and is blocked by the seat V32 from entering in to the Cylinders Other Pressure like BP and CR are charged at % kg/cm2
Brake Application During brake application application pressure pressure from Aux Reservoir buits up Cv pressure in the relay value which enters under the Diaphragm through choke D31. Pressure on bottom of Diaphragm lifts the value body (RV17) up thus opening the passage V32. Aux reservoir pressure then enters into the Brake Cylinders
Brake Cylinder pressure also enters on the top of Diaphragm assy via choke D32 and as soon pressure under and top of the Diaphragm assy are equal. Value body moved down (force of comp spring acting downwards) and closes the passage V32 The max value of Cv pressure is controlled by the max Pressure limiter in the DV a high controls the max brake cylinder pressure Release During release position first Cv Pressure gets released from the main position of the DV normal release position of DV) Brake cylinder pressure which is on top of Diaphragm assy in the relay value exhaust to atmosphere through open passage V31 (as pressure under the Diaphragm assy is less than the pressure on top this moves the Diaphragm assy down and thus opening passage V31) Disassembly of Relay value (Ref Fig )
-
Remov Removee strip strip (RV (RV -19 _ out of clamp clampin ing g ring ring (RV (RV -14) -14) using using a specia speciall circl circlip ip piler and remove supporting plate (RV -18) - Remove Diaphragm Diaphragm ( RV -13) -13) from from the housing housing and take take out value body (R (RV-17) - Take out out scre screw w plug plug (KD (KD -06) -06) and remo remove ve O-rin O-ring g (KD-0 (KD-05) 5)
Note: - Do not remove any other screw plugs bushing from the housing
Assembly of Relay Value Assemble the relay value in the reverse seque nce to disassembly Install the Diaphragm ( RV-13) in such a way that the sealing bead is located correctly in its groove in the relay value housing Note: - Use special nose plier to fix strip (RV-19) into the clamping ring (RV-14) Testing of relay value After assembly /overhaul test the individual relay value on the test bench Testing accessories -
moun mounti ting ng (Pt (Pt no no 4A5 4A5475 4753) 3) ‘T’ ‘T’ =1 No Pres Pressu sure re redu reduci cing ng val value ue ‘DM ‘DMV’ V’ = 1No 1No Isol Isolati ating ng cock cocks’ s’H1 H1,H ,H2, 2,H4 H4’’ =3 Nos Nos Three Three way way cloc clock k with with exha exhaust ust choke choke -1 No 0.8m 0.8mm m dia dia ‘H3’ ‘H3’ Chok Chokee 0.4 0.4 mm dia dia ‘D’ =1No =1No Pres Pressu sure re gaug gauges es 0-1 0-10 0 Kg/C Kg/Cm2 m2 =3 =3 No Res Reservo ervoir ir 3 Lit Litre -1 No Res Reservo ervoir ir 25 litre itre -1 No No
Procedure: (for your guidance working diagram of relay valu e is also shown) a) Mount Relay Relay value value (3) air tight tight on mounting mounting base base should should be plugged air air tight Remove Protection Cap (RV -07) b) Adjust Adjust pressure pressure reducing reducing value value (DMV) to to 5 kg/cm2 .Open .Open isolating isolating cock cock H2 c) Check inlet inlet value seat seat V32 for for leakage leakage by applying applying soap solutio solution n to exhaust exhaust port O. There should be no leakage d) Close cock cock H2 and open open cock H1 until until Cv pressur pressuree is 3.7 Kg/Cm2 Kg/Cm2 (Cv is is pressure pressure coming from top cover of DV) and record the charging time in reservoir C from 0 to 3.6 kg/cm2 (it should be 34 +- 2 secs ) The pressure difference between Cv and C shall not exceed 0.1 kg/cm2 e) Check Check out –let value value seat V31 for leakage leakage by applyi applying ng soap solutio solution n to exhaust exhaust port O . There should be no leakage
f) Open Open 3 way cock cock H3 and exhaus exhaustt Cv Pres Pressu sure re via 0.8 mm dia Chok Choke. e. Recor Record d drop in C pressure from 3.6 kg/cm2 to zero ( should be between 15 to 20 secs ) g) Re-charge Re-charge the Aux reservoir reservoir via via cock H2 charge charge Cv to 3.7 kg/cm2 kg/cm2 in small small steps steps via cock H3. Observe pressure gauges Cv and C and note the rise of Cc and C pressure is identical and with out any delay Observe the above by b y releasing the Cv pressure in steps h) Exhaust Exhaust all the pressur pressures es and remove remove the relay relay from the the mounting mounting base
Overhauling.
Overhaul the relay value along with the overhauling schedule of DV and replace the following components on every POH kit of DV approved by RDSO S.No 1 2 3 4 5 6
Part Name Diaphragm Sealing Ring Grooved Ring Sealing Ring O-Ring Sealing Ring
Part No RV-13 RV-20 RV-09 RV-21 KD-05 KD-04
No/off 1 1 1 1 1 1
Note: During overhand check other components also for any marks excessive wear or damage. Replace these with new parts
KBI CODE
DESCRIPTION
QTY
RV-08 RV-07 RV-05 RV-04 RV-09 RV-11 RV-10 RV-06 RV-21 RV-12 KD-06 KD-05 RV-20 RV-17 RV-13
COTTOR PIN PROTECTION CAP SCREWED PLUG SEALING RING GROOVED RING SUPPORTING RING COMPRESSION SPRING VALVE GUIDE SEALING RING FILTER SCREWED PLUG O- RING SEALING RING VALVE BODY DIAPHRAGM
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
RV-18 RV-14 KD-121 RV-03 KD-169A RV-02 RV-19 KD-170 RV-16 RV-15 RV-01
SUPPORTING PLATE CLAMPING RING SPRING WASHER HEX.HD.VOLT (M12*110) COUNTER SUNK SCREW M3*6 NAME PLATE STRIP SEALING RING CIRCLIP A10 WASHER BODY
TEST STAND FOR RELAY VALVE
1 1 1 1 1 1 1 1 1 1 1
TEST ACCESSORIES ACCESSO RIES FOR RELAY VAL VALVE: VE: 1. Pressure regulator valve
1
2. Isolating cocks
2,4,5,6
3. Reservoirs (75L)
3
4. Reservoirs (10L)
7
5.Pressure gauge (0-10 kg/cm2)
9,10
8.Bottom cover mounting base
8
RELAY VALVE
PREPARED TEST STAND FOR RELAY VALVE The required parts for the design of Test Stand
To prepare a Test Stand we need to having following c omponents. 1. Mounting “T” : 1 2. Pressure Reducing Value : 1 3. Isolating cocks H1, H2, H4 : 3 4. Three way cock with Exhaust choke : 1 0.8 mm dia ‘H3’ 5. Choke 0.4 mm dia ‘D’ 6. Pressure gauge (0-10 Kg/cm2) : 3 7. Reservoir : 3 liter. liter. 25 liter.
Mounting “T”: These is stand o which all accessories accessories are mounted, this act as a frame frame and support other part.
The material used for preparing this stand is ………………. We need to be specified about the dimensions of the stand to be prepared.
Pressure Reducing Value Value : Pressure reducing value play a major role. it supplies the required pressure to the cylinder what ever may be the pressure outcome from the cylinder. cylinder. Initial pressure present in the main reservoir is 12kg/cm2 but the required pressure is 6kg/cm2 for auxiliary reservoir and 5kg/cm2 for brake pipes. Isolating cocks Uses these are used to control direction of the pressure. Here we use three three isolating cocks H1= H2= H4= Three way cock: Three way cock is used to allow the pressure in three direction. H3= Choke Choke is small circular body with with a small hole in the middle the is used to increase the pressure . we can increase the pressure to required level by using the suitable choke. Pressure gauge
Press Pressure ure gauges gauges are the devices devices used used to measure measure the reservoirs her we used tha (0-10kg/cm2) pressure gauge.
pressu pressure re inside inside the
Reservoir Reservoir are used to store the pressure. As we the pressure plays a major role here storing the pressure is also important . so we use mildsteel cylinder to store the reuired pressure. Here for preparing the testshand we required 2 cylinder volume . 1. 3 li liter. 2. 25 li liter.
For Design the Reservoirs These following steps are to followed to design the cylinder 1. Requir Required ed volum volumes es are are to to know know first first.. 2. Dimensions Dimensions for the requir required ed volume volume are are to be calculat calculated ed a)3-liter we usually don’t find the 3-liter so we need to cut the 5-liter cylinder into 3-liter so we need cut the cylinder to the required dimension
1. Standard length(L1): 2. Circmfrence: 3. Standard Diameter: As we know
V = II/4 *D2 *L V= volume in liters. D=diameter in meters. L=length in meters.
3/1000 = II/4 * ()2 * L L2 = mtr. Required length for obtaining 3liter volume(L2)= volume(L2)= b) 25 liter As 25 liter liter is a standard standard cylinder cylinder we need not not design design or cut its its length length . its is is readily available 1. Standard length: 0.415mtr (415mm) 2. Circmfrence: 0.5597mtr (559mm) 3. Standard Diameter: 0.2768 mtr (276mm)
Intermediate plate
It is main main part of the test stand it can be considered as a heart of the test stand it act like a DV because as we can’t mount the whole DV assemble assemble to the test stand so the intermediate plate is e need to prepare, the part with similar feature of the DV For preparing the Intermediate plate
1. Take a metal metal bloc block k of requi required red dimen dimensio sions ns 2. Plot Plot the the dim dimen ensi sion onss on it 3. Perfor Perform m suitab suitable le operati operation on on lt like like a) Milling. b) Turning c) Step tep turni urning ng d) Groov ooving e) Threadi Threading( ng(Ext Extern ernal al threadi threading) ng) f) Drilling g) Reaming h) Taping( aping(Int Intern ernal al threa threadin ding) g) i) Finishing
RESULTS Periodic overhauling of the total air braking system must be done to make the air braking system work efficiently and to prevent major defects and there problems that could arise due to defects de fects in a Distributor valve Railways Air Brake system has a Test stand for testing an assembled D.V. but it does not have test stands for its sub assemblies.
The main objective of the project is Design and Fabrication of Test stand of sub assemblies of Distributor valves Many factors are taken into consideration for the Design of test stands for Bottom cover, choke cover, R-charger, Relay valve.
Factors are as follows:
1. Intermediate plate with suitable dimensions. 2. cylinders with required capacity. capacity. 3. Isolating cocks. 4. Pressure regulating valve. 5. pipes for connecting cylinders. 6. pressure gauges
CONCLUSIONS: After completing the above project, we can conclude that test stand prepared for sub assemblies is more useful than the previous( assembled DV) test stand.
1.
As time time is the the main main criteri criteriaa for testi testing, ng, time time taken taken for for repair repair,, replacem replacement ent Of Of the DV,s can be minimized.
2.
Les Less fat fatiigue gue for for the work worker er
3.
Rati Rating ng of over overha haul ulin ing g will will be incr increa ease sed d
4.
Testi esting ng of each each part part before before assemb assembli ling ng is useful useful for recti rectify fying ing the the defec defects ts in respective components
5.
Possib Possibili ilitie tiess of certai certain n fault faultss can can be elimin eliminated ated in advan advance. ce.
6.
Wasta astage ge of of mon money ey and and manp manpow ower er can can be avoi avoide ded d
REFERENCES: 1. Air Brakes system by b y P.C GUPTA. 2. Manual of Lallaguda work shop. 3. www. Indianrailway.org.
Routing 1. Working orking Princi Principle ple of of Air Air Braki Braking ng system system Introduction to BRAKE SYSTEM and its Classification & Components. • Introduction to AIR SYSTEM brakes & Working Working Principle. • Air Brake System and classification of Air Brakes. • Operation of Presently used Twin Pipe Graduated Release System. • Different Components of Air Brakes System. S ystem. • Comparison between Air Brakes AND Vacuum Vacuum Brakes System • Advantages of Air Brakes System over Vacuum Vacuum Brakes system. •
2. Study Study of of Distrib Distribut utive ive Valu Value. e. Distributive Value. • Function of the Distributive Value Value • Types of the Distributive Value • Operat Operation ion of Distri Distributi butive ve Value alue (Char (Chargin ging g Stage, Stage, Applic Applicati ation on Stage, Stage, • Release Stage). Study of sub Assemblies of Distributive Value •
3. Functio Functioning ning of major major Suba Subassem ssemblie bliess of Distribu Distributive tive.. Functioning of the Bottom Cover. • Functioning of the Choke Cover. • Functioning of the R-charger Cover. • Functioning of the Relay Cover. •
4. Stud Study y of Distribu Distributive tive Test stand. stand. Working principle principle of the Distributive Parameter • Pressure involved in functioning the DV • Pressure involved involved in each Subassemblies of DV • Parameter that are to be considered while Testing •
•
5. Collect Collecting ing feasibl feasiblee data for the the Design Design of the Relay Relay value value.. Data required for constructing the Test Test stand. • Material used for constructing the Test Test stand . • Calculating the required volume of reservoir • Design the Intermediate plate & process involved on Achieving it. • Gathering the other Required Parts like Isolating cocks, pressure Gauges, • pressures Reducing value , three way pressure value.
6. Mathematics Mathematics Calculation Calculation of the Reservoirs Reservoirs for the Test Stand. Stand. Calculating the diameter of the reservoir for 3liter & 25liter. • Estimating the length of the reservoirs. • Material used for cylinder •
7. Fabr Fabrica icatio tion n the cyli cylinde nderr. Constructing the cylinder cylinder with design parameter. parameter. • Performed the suitable operation on the obtaining the required dimensions • •
Preventive measurement are taken
8. Marking the required required dimensions dimensions of the the relay relay value on the Metal Metal block. block. Dimensions of the female part(Relay valve) and the male part(DV) are • taken Plot the male dimensions on the metal block (Intermediate plate) • Care is taken for the accuracy as it deals with the air • Take a metal block of 20*20 • 9. Perfor Performing ming seque sequentia ntiall operation operation on on the metal metal block block.. • • • • • • • • •
Vertical Milling(for accuracy) Turning Step turning Grooving Threading(External) Drilling Reaming Taping Finishing
10. Construction Construction of Mounting Stand for the Cylinder Cylinder And Intermediate Intermediate plate. Dimens Dimension ionss of the stand are taken by consid consideri ering ng dimens dimension ionss of the • cylinder and Intermediate plate. Taken individual length L-shape rods and jointed accordingly with the • required dimensions
•
11. Connecting Connecting Accessorie Accessoriess Required Required parts with hose Pipes as per line Diagram Diagram . Isolating Isolating Cocks , Pressure Pressure Reducing Value, Value, Pressure Pressure Gauges with hose • Pipes 12. Inspecting Inspecting of Designed Designed Test Test stand stand . Test the relay valve on the prepared test stand • 13. Giving Aesthetic look to the Test Test Stand. Total stand is covered with with the Cardboard to give it an aesthetic look • Aluminium l-shape are attached at corner for good look •
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