INDUSTRIAL TRAINING REPORT ON
(MECHANICAL) th
TH
DATE: 11 JUNE TO 9 JULY 2012(4 WEEKS) AT SECR (BILASPUR)
SUBMITTED BY:AGNIVESH BRANCH COLLEGE
P.SHARMA
:MECHANICAL SSEC,JUNWANI,BHILAI : SSEC,JUNWANI,BHILAI
I EXPRESS MY HEARTIEST GRATITUDE TO THE MR.LALIT DHURANDHAR SIR,SR.DME,SECR,BILASPUR
Indian Railways (reporting (reporting mark IR) is an iconic Indian organisation, owned and operated by the Government of India through the Ministry of Railways.. Indian Railways has 114,500 kilometres Railways (71,147 mi). of total track over a route of 65,000 kilometres (40,389 mi) and 7,500 stations. It has the world's fourth largest railway network after those of the United States, States, Russia and China China.. The railways carry over 30 million passengers and 2.8 million tons of freight of freight daily. In 2011-2012 Railway earnt 104,278.79 crore (US$ US$20.8 20.8 billion) which consists of 69,675.97 crore (US$ US$13.9 13.9 billion) from freight and 28,645.52 crore (US$ US$5.71 5.71 billion) from passengers tickets. Indian Railways is the world's fourth largest commercial or utility employer , by number of employees, with over 1.4 million employees.|~|
BCN DEPOT
bogies THE BOGIE FRAME AND COMPONENTS ARE OF ALLWELDED LIGHT CONSTRUCTION WIITH A WHEEL BASE OF 2.896M.THE WHEEL SETS ARE PROVIDED WITH SELFALIGHNING SPHERICAL ROLLER BEARINGS MOUNTED IN CAST STEEL AXLE BOX HOUSINGS.THE WEIGHT OF THE COACH IS TRANSFERRED THROUGH SIDE BEARERRS ON THE BOGIE BOLSTER.THE END OF THE BOGIE BOLSTER REST ON THE BOLSTER HELICAL SPRINGS PLACED OVER THE LOWEST SPRING BEAM SUSPENDED FROM THE BOGIE FRAME BY THE INCLINED SWING LINKS AT AN ANGLE 7’.
*BOGIE
BOLSTER SUSPENSION
:THE BOLSTERS
REST ON THE BOLSTER COIL SPRINGS TWO AT EACH ENDS,LOCATED ON THE LOWER SPRING BEAM WHHICH IS SUSPENDED FROM THE BOGIE SIDE FRAME BY MEANS OF BOLSTER SPRING SUSPENSION HANGERS ON EITHER SIDE. *SPRINGS:IN ICF BOGIES,HELICAL SPRINGS ARE USED IN BOTH PRIMARY AND SECONDARY SUSPENSION.THE SPRINGS ARE MANUFACTURED FROM PEELED AND CENTRELESS GROUND BAR OF CHROME,VANADIUM CHROME,MOLYBEDENUM STEEL CONFORMING TO STR NO.|~|
BOX-N BOX ICF BEML
25 20 16 10
BOXNHS
BOBRN
BOBY
BCN
BRHNEHS
BOXNHL
BOXNM
MM. MM MM MM
40 KGM 20 KGM 09 KGM 02GM 02 GM
WHEEL SPECIFICATIONS 1. NEW AND CONDEMNING SIZE OF WHEELS
IRS
SOLID
1000
990
996
TYRED
1000
1015
1021
BOXNBCN
SOLID
1000
925
931
BOXCRT
SOLID
1000
860
866
TYRED
1000
902
908
ICF
SOLID
915
813
819
TYRED
915
851
857
SOLID
914.5 813
819
TYRED 914.5 838
844
BEML
TYRED
-
-
(ALL THE DATA IS IN MM.)
-
2. WORN WHEEL PROFILE
28 MM THICKNESS *NEW — 28 *INTERMEDIATE PROFILE-25 MM
THICKNESS *INTERMEDIATE PROFILE-22 MM THICKNESS *INTERMEDIATE PROFILE-20 MM THICKNESS 3. LIMITS OF WHEEL DIA.FOR MANUAL ADJUSTMENT OF BRAKE GEAR ON BETWEENWHEEL DIA.ON TROLLEY
1000 & 982
981 & 963
962 & 944
943 & 925
924 & 906
HOLES TO BE USED FOR BRAKE ADJUSTMENT
a
b
c
d
e
BCN WAGON a
b
c
d
e
Ф=57 mm
THIN FLANGE-16 MM.(28.5MM)
SHARP FLANGE-5 MM.(14MM)
DEEP FLANGE-35 MM.(28.5MM)
THIN TYRE-LESS THAN NORMAL
FLAT SURFACE ON TYRE
HOLLOW TYRE-5 MM.HOLE ON SURFACE
ROUTE RADIUS LOW-13 MM(16 MM)
1. THE SPECIAL REPAIRS BY WORKSHOPS ARE THOSE REPAIRS WHICH CAN NOT BE DONE IN THE SICK LINE WITH THEIR EXISTING FACILITIES OR ARE SPECIFICALLY PROHIBITED PROHIBITED TO BE CARRIED OUT ON THE DIVISIONS. 2. SPECIAL REPAIR COACHES SHOULD BE SENT TO THE BOGIE WORKSHOPS ONLY AFTER OBTAINING THE PERMISSION OF THE CHIEF MECHANICAL ENGINEER AND ACCORDING TO THE CALLING IN PROGRAM OF THE WORKSHOP. 3. THE SUPERVISOR INCHARGE OF THE DEPOT SHOULD PREPARE A COMPLETE LIST OF DAMAGE AND DEFICIENCIES AND FORWARD IT TO DIVISIONAL MECHANICAL ENGINEER FOR GETTING PERMISSION OF THE CHIEF MECHANICAL ENGINEER TO BOOK THE COACH OF THE SHOP FOR NON-POH REPAIRS.A COPY OF THE LIST OF DAMAGES AND DEFICIENCIES SHOULD SIMULTANEOUSLY SIMULTANEOUSLY BE SENT TO THE WORKSHOP CONNECTED FOR PLANNING IT IN THEIR CALLING IN PROGRAMME.
An air brake is a conveyance braking system actuated by compressed air . Modern trains rely upon a fail-safe air brake system that is based upon a design patented by George Westinghouse on March 5, 1872. The Westinghouse Air Brake Company (WABCO) was subsequently organized to manufacture and sell Westinghouse's invention. In various forms, it has been nearly universally adopted. The Westinghouse system uses air pressure to charge air reservoirs (tanks) on each car. Full air pressure signals each car to release the brakes. A reduction or loss of air pressure signals each car to apply its brakes, using the compressed air in its reservoirs In the air brake's simplest form, called the straight air system , compressed air pushes on a piston in a cylinder . The piston is connected through mechanical linkage to brake shoes that can rub on the train wheels, using the resulting friction to slow the train. The mechanical linkage can become quite elaborate, as it evenly distributes force from one pressurized air cylinder to 8 or 12 wheels. The pressurized air comes from an air compressor in the locomotive and is sent from car to car by a train line made up of pipes beneath each car and hoses between cars. The principal problem with the straight air braking system is that any separation between hoses and pipes causes loss of air pressure and hence the loss of the force applying the brakes. This deficiency could easily cause a runaway train. Straight air brakes are still used on
locomotives, although as a dual circuit system, usually with each bogie (truck) having its own circuit. In order to design a system without the shortcomings of the straight air system, Westinghouse invented a system wherein each piece of railroad rolling stock was equipped with an air reservoir and reservoir and a triple valve , also known as a control valve .
Rotair Valve Westinghouse Air brake Company[1] The triple valve is described as being so named as it performs three functions: Charging air into an air tank ready to be used, applying the brakes, and releasing them. In so doing, it supports certain other actions (i.e. it 'holds' or maintains the application and it permits the exhaust of brake cylinder pressure and the recharging of the reservoir during the release). In his patent pat ent application, Westinghouse refers to his 'triple-valve device' because of the three component valvular parts comprising it: the diaphragm-operated poppet valve feeding reservoir air to
the brake cylinder, the reservoir charging valve, and the brake cylinder release valve. When he soon improved the device by removing the poppet valve action, these three components became the piston valve, the slide valve, and the graduating valve.
If the pressure in the train line is lower than that of the reservoir , the brake cylinder exhaust portal is closed and air from the car's reservoir is fed into the brake cylinder to apply the brakes. This action continues until equilibrium between the brake pipe pressure and reservoir pressure is achieved. At that point, the airflow from the reservoir to the brake cylinder is lapped off and the cylinder is maintained at a constant pressure. If the pressure in the train line is higher than that of the reservoir, the triple valve connects the train line to the reservoir feed, causing the air pressure in the reservoir to increase. The triple valve also causes the brake cylinder to be exhausted to the atmosphere, releasing the brakes. As the pressure in the train line and that of the t he reservoir equalize, the triple valve closes, causing the air pressure in the reservoir and brake cylinder to be maintained at the current level.
Unlike the straight air system, the Westinghouse system uses a reduction in air pressure in the train line to apply the brakes. When the engineer (driver) applies the brake by operating the locomotive brake valve, the train line vents to atmosphere at a controlled rate, reducing the train line pressure and in turn triggering the triple valve on each car to feed air into its brake cylinder. When the engineer releases the brake, the locomotive brake valve
portal to atmosphere is closed, allowing the train line to be recharged by the compressor of the locomotive. The subsequent increase of train line pressure causes the triple valves on each car to discharge the contents of the brake cylinder to the atmosphere, releasing the brakes and recharging the reservoirs. Under the Westinghouse system, therefore, brakes are applied by reducing train line pressure and released by increasing train line pressure. The Westinghouse system is thus fail safe — any any failure in the train line, including a separation ("break-in-two") of the train, will cause a loss of train line pressure, causing the brakes to be applied and bringing the train to a stop, thus preventing a runaway train. Modern air brake systems are in effect two braking systems combined:
The service brake system, which applies and releases the brakes during normal operations, and The emergency brake system, which applies the brakes rapidly in the event of a brake pipe failure or an emergency application by the engineer.
When the train brakes are applied during normal operations, the engineer makes a "service " service application" or a "service rate reduction”, which means that the train line
pressure reduces at a controlled rate. It takes several seconds for the train line pressure to reduce and consequently takes several seconds for the brakes to apply throughout the train. In the event the train needs to make an emergency stop, the engineer can make an "emergency application," which immediately and rapidly vents all of the train line pressure to atmosphere, resulting in a rapid application of the train's brakes. An
emergency application also results when the train line comes apart or otherwise fails, as all air will also be immediately vented to atmosphere. In addition, an emergency application brings in an additional component of each car's air brake system: the emergency portion. The triple valve is divided into two portions: the service portion, which contains the mechanism used during brake applications made during service reductions, and the emergency portion, which senses the immediate, rapid release of train line pressure. In addition, each car's air brake reservoir is divided into two portions — the the service portion and the emergency portion — and and is known as the "dual-compartment reservoir”. Nor mal mal service applications transfer air pressure from the service portion to the brake cylinder, while emergency applications cause the triple valve to direct all air in both the service portion and the emergency portion of the dual-compartment reservoir to the brake cylinder, resulting in a 20 – 30% 30% stronger application. The emergency portion of each triple valve is activated by the extremely rapid rate of reduction of train line pressure. Due to the length of trains and the small diameter of the train line, the rate of reduction is high near the front of the train (in the case of an engineerinitiated emergency application) or near the break in the train line (in the case of the train line coming apart). Farther away from the source of the emergency application, the rate of reduction can be reduced to the point where triple valves will not detect the application as an emergency reduction. To prevent this, t his, each triple valve's emergency portion contains an auxiliary vent port, which, when activated by an emergency application, also
locally vents the train line's pressure directly to atmosphere. This serves to propagate the emergency application rapidly along the entire length of the train. Use of distributed of distributed power (i.e., power (i.e., remotely controlled locomotive units midtrain and/or at the rear end) mitigates somewhat the time-lag problem with long trains, because a telemetered radio signal from the engineer in the front locomotive commands the distant units to initiate brake pressure reductions that propagate quickly through nearby cars.|~|
SCHEMATIC DIAGRAM OF AIR BRAKE SYSTEM
ICF Bogie is a conventional railway bogie used on the majority of Indian of Indian Railway main line passenger coaches. The design of the bogie was developed by ICF (Integral Coach Factory) Factory), Perumbur , India in collaboration with the Swiss Car & Elevator Manufacturing Co., Schlieren Schlieren,, Switzerland in the 1950s. The design is also called the Schlieren design based on the location of the Swiss company. The bogie can be divided into various subsections for easy understanding as follows: Bogie frame The frame of the ICF bogie is a fabricated structure made up of mild steel channels and angles welded to form the main frame of the bogie.The frame is divided into three main sections. The first and the third section are mirror images of each other. Various types of brackets are welded to the frame for supporting bogie components. Bogie bolster The body bolster is a box type fabricated member made up of channels and welded to the body of the coach. It is a free-floating member. The body bolster transfers the dead weight of the coach body to the bogie frame. There are two type of bolsters in an ICF
bogie: body bolster and the bogie bolster. The body bolster is welded to the coach body whereas the bogie bolster is a free floating member which takes the entire load of the coach through the body bolster.In body bolster there are 2 side bearers and a center pivot pin are joined by excellent quality welding. These three parts acts as a male part and matches with the female part welded to bogie bolster. These are very vital parts for smooth running of a train. Center pivot pin A center pivot pin is bolted to the body bolster. The center pivot pin runs down vertically through the center of the bogie bolster through the center pivot. It allows for rotation of the bogie when the coach is moving on the curves. A silent block, which is cylindrical metal rubber bonded structure, is placed in the central hole of the bogie bolster through which the center pivot pin passes. It provides the cushioning effect. Wheel set assembly Wheel arrangement is of Bo-Bo type as per the UIC classification. The wheel set assembly consists of two pairs of wheels and axle. The wheels may be cast wheels or forged wheels. The wheels are ar e manufactured at Durgapur Steel Plant of SAIL( Steel authority of India Ltd.) or at Wheel and Axle Plant of Indian Railways bases at Yelahanka near Banglore in the state of Karnataka. At times, imported wheels are
also used. These wheels and axles are machined in the various railway workshops in the wheels shops and pressed together. Roller bearing assembly Roller bearings are used on the ICF bogies. These bearings are press fitted on the axle journal by heating the bearings at a temperature of 80 to 100 °C in an induction furnace. Before fitting the roller bearing , an axle collar is press fitted. The collar ensures that the bearing does not move towards the center of the axle. After pressing the collar, a rear cover for the axle box is fitted. The rear cover has two main grooves. In one of the grooves, a nitrile rubber sealing ring is placed. The sealing ring ensures that the grease in the axle box housing does not seep out during the running of the wheels. A woolen felt ring is placed in another groove. After the rear cover, a retaining ring is placed. The retaining ring is made of steel and is a press fit. The retaining ring ensures that the rear cover assembly is secured tightly between the axle collar and the retaining ring and stays at one place. The roller bearing is pressed after the retraining ring. Earlier, the collar and the bearings were heated in an oil bath. But now the practices has been discontinued and an induction furnace is used to heat them before fitting on the axle. The axle box housing, which is a steel casting, is then placed on the axle. The bearing is housed in the axle box housing. Axle box grease is filled in the
axle box housing. Each axle box housing is filled with approximately 2.5 kg. of grease. The front cover for the axle box is placed on a housing which closes the axle box. The front cover is bolted by using torque wrench. Brake beam assembly ICF bogie uses two types of brake beams. 13 ton and 16 ton. Both of the brake beams are fabricated structures. The brake beam is made from steel pipes and welded at the ends. The brake beam has a typical isosceles triangle shape. The two ends of the brake beam have a provision for fixing a brake head. The brake head in turn receives the brake block. The material of the brake block is non asbestos, and nonmetallic in nature. Brake head Two types of brake heads are used. ICF brake head and the IGP brake head. A brake head is a fabricated structure made up of steel plates welded together. Brake blocks Brake blocks are also of two types. ICF brake head uses the "L" type brake block and the "K" type brake block is used on the IGP type brake head. "L" & "K" " K" types are so called since the shape of the brake blocks resembles the corresponding English alphabet letter. The third end of the brake beam has a bracket for connecting the "Z" & the floating lever. These levers are connected to the main frame of the bogie
with the help of steel brackets. These brackets are welded to the bogie frame. Brake levers Various type of levers are used on the ICF Bogie . The typical levers being the "Z" lever, floating lever and the connecting lever. Theses levers are used to connect the brake beam with the piston of the brake cylinder. The location of the brake cylinders decides whether the bogie shall be a BMBC Bogie or a non BMBC Bogie. Conventional bogies are those ICF bogies in which the brake cylinder is mounted on the body of the coach and not placed on the bogie frame itself. Brake cylinder In a ICF BMBC Bogie, the brake cylinder is mounted on the bogie frame itself. Traditionally, the ICF Bogies were conventional type i.e. the brake cylinder was mounted on the body of the coach. However, in the later modification, the new bogies are being manufactured with the BMBC designs only. Even the old type bogies are being converted into BMBC Bogies. The BMBC bogie has many advantages over the conventional ICF bogie. The foremost being that, since the brake cylinder is mounted on the bogie frame itself and is nearer to the brake beam, the brake application time is reduced. Moreover, a small brake cylinder is adequate for braking purpose. This also reduces the overall weight of the ICF bogie apart from the advantage of quick brake application.
Primary suspension The primary suspension in a ICF Bogie is through a dashpot arrangement. The dashpot arrangement consists of a cylinder (lower spring seat) and the piston (axle box guide). Axle box springs are placed on the lower spring seat placed on the axle box wing of the axle box housing assembly. A rubber or a Hytrel washer is placed below the lower spring seat for cushioning effect. The axle box guide is welded to the bogie frame. The axle box guide acts as a piston. A homopolymer acetyle washer is placed on the lower end of the axle box guide. The end portion of the axle box guide is covered with a guide cap, which has holes in it. A sealing ring is placed near the washer and performs the function of a piston ring. The axle box guide moves in the lower spring seat filled with dashpot oil. This arrangement provides the dampening effect during the running of the coach. Dashpot arrangement The dashpot arrangement is mainly a cylinder piston arrangement used on the primary suspension of Indian Railway coaches of ICF design. The lower spring seat acts as a cylinder and the axle box guide acts as a piston. The dashpot guide arrangement has the t he following main components: Lower Spring Seat Lower Rubber Washer Compensating Ring. Guide Bush Helical Spring Dust Shield. Circlip. Dust Shield Spring. Protective Tube Upper Rubber Washer. Axle Box Guide Screw with sealing washer The axle box guide
(piston) is welded to the bottom bot tom flange of the bogie side frame. Similarly, the lower Spring seat (cylinder) is placed on the axle box housing wings forms a complete dashpot guide arrangement of the ICF design coaches. Axle box guides traditionally had a guide cap with 9 holes of 5mm diameter each; however, in the latest design, the guide cap is made an integral part of the guide. Approximately 1.5 liters of dashpot oil is required r equired per guide arrangement. Air vent screws are fitted on the dashpot for topping of oil so that the minimum oil level is maintained at 40mm. Traditionally, rubber washers have been used at the seating arrangement of the primary springs of the axle box housing in the ICF design passenger coaches on the Indian Railways. The rubber washer is used directly on the axle box seating area. the lower spring seat sits on the washers. The lower spring seat is a tubular structure and 3/4 section is partitioned by using a circular ring which is welded at the 3/4 section. On the top of spring seat, a polymer ring called NFTC ring sits. The primary spring sits on the NFTC ring. The lower spring seat plays the role of a cylinder in the dashpot arrangement and is filled with oil. In the dashpot arrangement, the top portion is called the axle box guide. The axle box guide is welded to the bogie frame. The axle box guide works as a piston in the Lower spring seat filled with oil. This helps in damping the vibrations caused during running train operation. The axle box guide, which is welded to the bogie frame has a polymer washer (homopolymer acetal guide) bush fixed at the head. A polymer packing ring and a guide ring is attached with the Acetal guide bush. These two components act as piston rings for the axle box guide. In
order to ensure that the packing ring and the guide ring retain their respective place, a dashpot spring is fixed which applies continuous pressure on the piston ring. The bottom of the axle box guide has a guide cap with perforations so that during the t he downward movement of the axle guide in the lower spring seat, the oil in the dashpot rushes in the axle box guide. This provides the dampening of vibration in a running coach. The guide cap is fixed with the help of a steel circlip. However in the new design of Axle box guide, the guide cap is welded with the guide assembly and hence the need of a guide cap has been eliminated. The complete guide and lower spring arrangement is covered with a dashpot cover also known as protective tube. The protective tube has a circular ring over it called the dust shield which prevents the ingress of the dust in the cylinder piston arrangement of the dashpot. Spring seating As described above, the rubber washers sit directly on the axle box spring sitting area. Earlier,wooden washers were used. However, with the development of technology, rubber washers replaced wooden washers. Presently, RDSO, Lucknow which is a Research, Design & Standardization organization for the Indian Railways developed a new design for washers made from a polymer commonly known as HYTREL. Hytrel polymer is a product of M/s DuPont . The reason for replacement of the rubber washers with the hytrel washers was that the rubber washers were not lasting for the full Periodic overhaul cycle of the Railway Coaches which was one year. The washers also had to be
replaced in the coaching maintenance depots leading to lifting and lowering of coaches. Introduction of Hytrel washers was considered a breakthrough in the ICF dashpot design. However, the mass scale replacement of the rubber washers by Hytrel washers without adequate trials lead to massive failure of the axle Box housing. The hardness of the washers as per the specified limits was to be 63+- 5 Shore D hardness. Another parameters was the load deflection characteristics of the washers. A study was carried out on a major workshop on Indian Railways and it was found that the washers were having a hardness more than the specified limits. Moreover, Moreover, the load deflection characteristic of the washers were also not found to be in line with the desired specification. Within 6 months of provision of Hytrel washers on all the main line coaches, the failure of Axle box housing increased. The reason was the axle box wing cracks. Hence on examination of the failed axle boxes, it was noticed that the Hytrel washers were forming a deep groove of 4 to 8mm on the seating area of the axle box spring seating. They washers were also increasing the diameter of the spring seating due to continuous hitting of the raised section of the sitting area. The coaches come to the workshop once in a year. During examination of these coaches , it was noticed that the Hytrel washers have not only damaged the axle box housing but also the lower spring seat as well as the Protective tube. To prevent such damage, RDSO, Lucknow issued a guideline asking the Railways to provide a delrin liner
below the Hytrel washers. However, it was indicated that these liners are to be provided only on new coaches and in coaches in which new wheels are fitted. A look at the drawing of the dashpot arrangement will suggest that this problem is universal for all the coaches, whether a new coach or an old coach. Moreover, the provision of the liners below the Hytrel washers will not stop the damage to the lower spring seat and the protective tube. Problem of oil spillage The problem of spilling of oil from the dashpot is as old as the design itself. Numerous design changes have been implemented in the last many years however, the problem of oil spillage is still a challenge. The cylinder piston arrangement of the dashpot, i.e. the Lower Spring seat and the axle box guide is not fully sealed due to the limitation of the design and practical applicability. Its design provides that when a vertical vibration occurs during the movement of the railway coach, the axle box guide moves down. The downward movement of the Axle box guide puts pressure on the oil in the lower spring seat. The oil rushes up. However, since there are holes in the guide cap, the oil passes through these holes into the hollow body of the axle box guide. This helps in dampening the vertical vibrations. The axle box guide displaces the oil in the lower spring seat and pushes it upwards. Since, only part quantity of oil is able to move up in the hollow portion of the axle box guide, the balance displaced oil moves up. As per correct maintenance practice, it is to be ensured that the hole in the guide are in alignment with
corresponding holes in the guide bush. However, this is practically difficult to maintain in the shop floor of bogie shop. As the top portion of the lower spring seat is not sealed and only covered with the help of a protective tube also called the dashpot cover, the rising oil has a tendency to shoot above the top rim of the lower spring seat and spill out. Oil spillage can be prevented by the t he following actions: a. Change the dashpot design from the cylinder piston arrangement to hydraulic shock absorbers. b. Increase the hole diameter from 5mm in the guide cap to more than the t he existing diameter. However, it must be ensured that the increased diameter of the holes of the guide cap does not lead to less dampening effect. c. Provide a conical arrangement above the rim of the lower spring seat up to half the height of the dashpot cover. However, the clearances of the protective tube and the outer dia of the proposed conical section at the top of the lower spring seat needs to be taken care of d. Modify the dust shield ring by incorporating a rubber component in it in such a manner that it also acts as an oil seal e. Ensure that the hole in the guide are in alignment with corresponding holes in the guide bush Some of these proposed modifications have already been tried out on the Indian Railways, however, the trials have not yielded a consistent positive feedback.
Buffer Height adjustment The wheel diameter(tread) reduces due to brake application as the brake blocks rub against the wheel tread. Over a period of time, the wheel diameter reduces up to 819 mm. 819mm is the condemnation diameter for the wheels. This diameter is also not sacrosanct and is changed depending upon the supply position of the wheels. The maximum variation in the wheels on the same axle is permitted up to 0.5 mm , between two wheels of the same bogie up to 5 mm and among the four wheel sets of the same coach up to 13 mm. The diameter of a new wheel is 915 mm. Hence maximum wheel tread wear allowed is (915 mm - 819mm) = 96 mm. In order to adjust for the difference in the wheel tread, a packing is placed under the flange of the lower spring seat. This packing ring is generally made up of NFTC(Natural Fiber Thermosetting COMPOSITE) or UHMWPE or UHMWPE (Ultra-high molecular weight polyethylene) material. The thickness of the NFTC packing ring is equal to 50% of the difference between the dia of a new wheel and the wheel in question. Traditionally, 13mm, 26mm, 38mm, 48 mm packing rings are used. They correspond to wheel diameter of 899-864, 862-840, 839-820 and 819 mm. The correct buffer height is obtained by measuring the height of the bolster top surface from the rail level. In case the buffer height is still not obtained even after placement of the packing ring, then compensation rings are to be inserted below the axle box spring ensuring that the bogie frame height is within 686 + - 5 mm. Secondary suspension The secondary suspension arrangement of the ICF bogies is through bolster springs. The bogie bolster is
not bolted or welded anywhere to the bogie frame. It is attached to the bogie frame through the anchor link. The anchor link is a tubular structure with cylindrical housing on both the ends. The cylindrical housings have silent blocks placed in them. The anchor link is fixed to the bogie bolster and the bogie frame with the help of steel brackets welded to the bogie bolster and the bogie frame. Both the ends of the anchor link act as a hinge and allow movement of the bogie bolster when the coach is moving on a curved track. Lower spring beam The bolster springs are supported on a lower spring beam. The lower spring beam is a fabricated structure made of steel plates. It is trapezoidal in shape with small steel tubes on each end. The location of the bolster spring seating is marked by two circular grooves in the center. A rubber washer is placed at the grooved section. The bolster spring sits on the rubber washer. The lower spring beam is also a free-floating structure. It is not bolted or welded either to the bogie frame or the bogie bolster. It is attached to the bogie frame on the outside with the help of a steel hanger. They are traditionally called the BSS Hangers (Bogie Secondary Suspension Hangers). A BSS pin is placed in the tubular section in the end portion of the lower spring beam. A hanger block is placed below the BSS pin. The BSS hanger in turn supports the hanger. This arrangement is done
on all the four corners of the lower spring beam. The top end of the hanger also has a similar arrangement. However, instead of the BSS pin, steel brackets are welded on the lower side of the bogie frame of which the BSS hanger hangs with the help of hanger block. This arrangement is same for all the four top corners of the hangers. Hence, the lower spring beam also become a floating member hinged to the bogie frame with the help of hangers on the top and the bottom. This allows for the longitudinal movement of the lower spring beam. Equalizing stay rod The inner section of the lower spring beam is connected to the bogie bolster with the help of an equalizing stay rod. It is a double Y-shaped member fabricated using steel tubes and sheets. The equalizing stay rod is also hinged on both the ends with the lower spring beam as well as the bogie bolster with the help of brackets welded to the bogie bolster. They are connected through a pin making it a hinged arrangement.|~|
TYPE OF AC COACHES ON RAILWAYS CAN BE CLASSIFIED ON THE BASIS OF POWER SUPPLY SYSTEM AS: 1. END ON GENERATION(EOG):IN THIS SYSTEM TWO TYPES OF POWER CARS ARE USED a) COACHES MOUNTED WITH 50 KVA,750 V/415 V,3 PHASE TRANSFORMER b) COACHES WITHOUT STEPDOWN TRANSFORMER SUITABLE ONLY FOR OLD LOW CAPACITY POWER CARS. 2. SELF GENERATING(SG):BASED ON AC EQUIPMENTS THERE ARE TWO TYPES OF SELF GENERATING COACHES a) 110 V WITH UNDER SLUNG TYPES AC EQUIPMENTS WORKING FROM 110 DC b) 110 V DC WITH ROOF MOUNTED AC PACKAGE UNITS WORKING FROM 415 V,3PHASE OBTAINED WITH THE HELP OF 25 KVA INVERTERS MOUNTED ON UNDERSLUNG AS WELL AS ONBOARD. MAJOR EQUIPMENTS USED IN AC UNIT ARE – 1. CONDENSER INCLUDING LIQUID RECEIVERS AND DEHYDRATOR. 2. EXPANSION VALVE 3. EVAPORATOR WITH HEATER ELEMENT
4. MOTORS FOR COMPRESSOR,CONDENSER, EVAPORATOR 5. THERMOSTAT,FILTERS ETC.
A YELL OW
B OXFO RD BLUE
C GREE N
ALL NON AC ICF TYPE
33.5
275-295 279- 285- 290284 289 299
ALL AC ICF TYPE
33.5
264-282 264- 270- 276269 275 282
HIGH CAPACI TY PARCE L VAN
39
276-275 276- 280- 285279 284 289
A YELL OW
B C OXFO GREE RD N BLUE
ALL NON AC ICF TYPE
42
385
3300
301-317
301- 306- 312305 311 317
ALL AC ICF TYPE
42
400
4800
295-308
291- 297- 304296 303 308
HIGH CAPACI TY PARCE L VAN
32. 286 5
6000
256-272
256- 262- 268261 267 272
1.DOOR REPAIRING 2.WHEEL CHANGING 3.CBC REPAIRING 4.BRAKE SHOE REPLACING 5.WELDING/CUTTING 6.SCRAPPING 7.BRAKE SYSTEM CHANGING
1.BOXNHS 2.BOBRN 3.BOBY 4.BCN 5.BRHNEHS 6.BOXNM 7.BOXNHL
1. BODY GEAR 2. UNDER GEAR 3. BUFFERING GEAR 4. ROLLING GEAR
1. SAB-SLACK ADJUSTING BARREL 2. BRAKE CYLINDER 3. AIR RESERVOIR 4. DISTRIBUTIVE VALVE 5. BRAKE PIPE
1.AIR BRAKE SYSTEM:IT IS COMMONLY USED NOWADAYS IN GOODS AS WELL AS PASSENGER CARRIAGES.IT USES COMPRESSED AIR TO STOP THE TRAIN.IT CONSISTS OF 5 KG OF COMPRESSED AIR PRESSURE.TWO PIIPES NAMELY F.P&B.P. ARE USED TO CONNECT THE BRAKE SYSTEM OF TWO BOGIES.IN PRESENT DAYS ONLY ONE PIPE IS USED AS IT MAKES THE SYSTEM QUICK WORKING AND QUICK RELEASING. 2. VACCUME BRAKE SYSTEM:NOT USED NOW A DAYS.USED VACCUME TO STOP THE TRAIN.
CBC(CENTRAL BUFFER COUPLER) IS USED IN TRAINS TO JOIN TWO BOGIES.IT CONSIST OF A HOOK LIKE COUPLER WHICH COMBINES WITH THE COUPLER OF OTHER BOGIE AND FORMS A STRONG BOND BETWEEN THEM. CBC IS OF TWO TYPES: 1.TRANSITION TYPE: BOGIES HAVING TRANSITION TYPE COUPLER HAVE A FACILITY OF SCREW COUPLING ALONG WITH THE CENTRAL COUPLER.HENCE GOODS TRAIN HAVING THIS TYPE OF COUPLING CAN BE JOINED WITH COACHES ALSO. 2.NON-TRANSITION TYPE: THEY HAVE ONLY CENTAL COUPLER AND CAN BE JOINED ONLY WITH OTHER GOODS CARRIAGES.
