CAMTECH/S/2001/Basic Concepts/SCR-4
COURSE CONTENTS 1.
Knowledge and necessity of Signals – Fail Safe Feature of Signaling System
2.
Definition of Signaling terms as given G & SR
3.
Concept of LQ; UQ Signaling; Colour Light Signals
4.
Overlaps; Braking distances: Sighting Distance
5.
Location of Signals
6.
Subsidiary Signals
7.
Markers, Boards, Signs, etc.
8.
Isolation, Slip Siding & Catch Siding
9.
Simultaneous Reception and dispatch of trains
10.
Classification of stations – Minimum signaling equipments required at each class of station
11.
Standards of Inter Locking – Minimum Signaling equipments required at each standard of inter locking.
12.
Level crossing gates
13.
Inter cabin control
14.
System of train working (Block Working)
15.
Control of outlying sidings through Block Instruments
16.
Station Working rules
17.
Signaling Plan
1
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Lesson Plan
Long Course No. of Hours
Topic Knowledge and necessity of
Theory
Practicals
Teaching Aids Theory
Practicals
1
signals – fail safe feature of signaling system. Definition of signaling terms as
3
given in G & SR Concept of LQ, UQ signaling color
2
OHP Wallchart
2
OHP
light signals Overlaps, braking distance, sighting distance Location of signals
3
2
OHP Wallchart
Model Room
Subsidiary signals
2
2
OHP Wallchart
Model Room
Markers, Boards, Signs, etc
3
2
OHP Wallchart
Model Room
Isolation, slip siding, catch siding
2
2
OHP
Model Room
Simultaneous reception and
2
2
4
2
Model Room
dispatch of trains Classification of station – minimum signaling equipments required at
Block board
Model Room
OHP
each class of station Standards of signaling – minimum
4
2
OHP Wallchart
Model Room
Level crossing gates
2
2
OHP
Model Room
Inter cabin control
2
2
OHP
Model Room
System of train working (block
4
2
OHP Wallchart
Model Room
Block instruments, methods of block working, control of outlying sidings Station working rules
6
3
OHP Wallchart
Model Room
2
2
OHP
Open Line
Signaling plan
2
1
OHP Wallchart
Open Line
signaling equipments required each standard of signaling
working)
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Lesson Plan
Short Course Minutes
Topic Knowledge and necessity of
Theory
Practicals
Teaching Aids Theory
Practicals
20
signals – fail safe feature of signaling system. Definition of signaling terms as
30
OHP
30
OHP Wallchart
20
OHP
given in G & SR Concept of LQ, UQ signaling color light signals Overlaps, braking distance, sighting distance Location of signals
20
15
OHP Wallchart
Model Room
Subsidiary signals
20
20
OHP Wallchart
Model Room
Markers, Boards, Signs, etc
30
Isolation, slip siding, catch siding
25
Simultaneous reception and
20
OHP Wallchart 30
OHP
Model Room
OHP
dispatch of trains Classification of station – minimum
30
30
OHP Wallchart
Model Room
60
30
OHP Wallchart
Model Room
signaling equipments required at each class of station Standards of signaling – minimum signaling equipments required each standard of signaling Level crossing gates
30
OHP Wallchart
Inter cabin control
20
OHP Wallchart
System of train working (block
60
60
OHP Wallchart
Model Room
30
30
OHP
Model Room
working) Block instruments, methods of block working, control of outlying sidings Station working rules
30
OHP
Signaling plan
30
OHP
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NECESSITY OF SIGNALS Signaling Concepts :
Railway vehicles move on steel rail track and engines, wagons and coaches are provided with flanged steel wheels. The rolling of steel wheels on the steel rail has the least friction and therefore, it is the most efficient means of locomotion.
Unlike road vehicles, railways have no capacity to steer away. They have to follow a fixed path, as guided by these rails. They are required to follow one another.
Precedence and crossings can be arranged only at station.
Drivers of a
locomotive has only control over the speed of the train, he can start and stop. This communication to the driver to proceed or to stop is through signals.
What are Signals : Signal is medium to convey a particular predetermined meaning in non-verbal form. Signals of non-verbal form are also used in road transport, navy and air traffic control etc.
Fixed Signals : A signal of fixed location indicating the condition affecting movement of train. It includes Semaphore arm, or a disc or fixed light used by day or night.
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Semaphore is a Greek word. SEMA stands for Sign, PHERO means bear. Semaphore signal is rectangular or fish tailed at the end. Fixed on a vertical post, kept horizontal. Easily distinguishable from longer distances. There are three methods of display : i)
Vertical
-
Parallel to post.
ii)
Midway Position
-
below horizontal.
iii)
Midway Position
-
above horizontal.
Various Forms of Signals : Signals
Visual
Audible
Detonators
Movable
Semaphore
LQ
UQ
Fixed
Voice
Flare
CLS
2 Aspect
Position Light
Multiple Aspect
Whistle
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DEFINITIONS (As per GR 1.02) ACT
:Means the Indian Railways Act, 1989.
ADEQUATE DISTANCE
:Means the distance sufficient to ensure Safety.
APPROACH LIGHTING
:Means an arrangement in which the lighting of signals is controlled automatically by the approach of a train.
APPROVED SPECIAL INSTRUCTIONS : Means special instructions approved of or prescribed by the Commissioner of Railway Safety.
AUTHORISED OFFICER
:Means the person who is duly empowered by general or special order of the Railway. Administration, either by name or by virtue of his office, to ensure instructions or to do any other thing.
AUTHORITY TO PROCEED
:Means the authority given to the driver of a train, under the system of working, to enter the block section with his train.
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AXLE COUNTER
7
:Means an electrical device which, when provided at two given points on the track proves by counting axles in and counting axles out. Whether the section of the track between the said two points is clear or occupied.
BLOCK BACK
:Means to dispatch a message from a block station intimating to the block station immediately in rear on a double line or to the next block station on either side on a single line, that the block section is obstructed or is to be obstructed.
BLOCK FORWARD
:Means to dispatch a message from a block Station on a double line intimating to the block station immediately in advance the fact that the block section in advance is obstructed or is to be obstructed.
BLOCK SECTION
:Means that portion of the running line between two block stations on to which no running train may enter until line clear has been received from the block station at the other end of the block station.
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COMMISSIONER OF RAILWAY SAFETY : Means a Commissioner of Railway safety appointed to exercise any functions under the
act
and
includes
the
chief
Commissioner of Railway safety.
CONNECTIONS
: When used with reference to a running line, means the points and crossings, or other appliances used to connect such line with other lines to cross it.
DIRECTION OF TRAFFIC
: a). On a double line, the direction for which the line is signaled. b). On a single line, the direction for the time being established, under the system of working to allow trains to move in that direction.
FACING AND TRAILING POINTS : Points are facing or trailing in accordance with the direction of a train or vehicles moves over them. Points are said to be facing points when by their operation a train
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approaching them can be directly diverted from the line upon which it is running.
FIXED SIGNAL
: Means a signal of fixed location indicating a condition affecting the movement of a train and includes a Semaphore arm or disc or fixed light for use by day and fixed light for use by night.
FOULING MARK
:
Means
the
marks
at
which
the
infringement of fixed standard dimensions occurs, where two lines cross or join one another.
INTER LOCKING
: Means an arrangement of signals, points and other appliances, operated from a panel or lever frame, so inter connected by Mechanical locking or Electrical locking or both that their operation must take place in proper sequence to ensure safety.
INTERMEDIATE BLOCK POST : Means a class “C” station on a double line, remotely controlled from the block station in rear.
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INTERMEDIATE BLOCK SIGNALLING : Means an arrangement of signalling on double line in which a long block section is split in two portions each constituting a separate block section by providing an Intermediate Block post.
ISOLATION
: Means an arrangement, secured by the settings of points or other approved means to protect the line so isolated from the danger of obstruction from other connected line or lines.
LAST STOP SIGNAL
: Means the fixed stop signal of a station controlling the entry of a train into the next block station.
LEVEL CROSSING
: Means the intersection of road with railway track at the same level.
LINE CLEAR
: Means the permission given from a block station to a block station in rear for a train to leave the latter and approach the former, or
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the permission obtained by a block station from a block station in advance for a train to leave the former and proceed towards the latter.
MAIN LINE
: Means the line ordinarily used for running trains through and between stations.
MULTIPLE ASPECT SIGNALLING : Means a signalling arrangement in which signal displays at any one time any one of the three or more aspects and in which the aspect of every signal is pre-warned by the aspect of the previous signal or signals.
OBSTRUCTION
: And its cognate expressions include a train, vehicle or obstacle on or fouling a line, or any condition, which is dangerous to trains.
POINT AND TRAP INDICATORS : Are not signals, but are appliances fitted to and working with points to indicate by day or by night the position in which the points are set.
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RUNNING LINE
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: Means the line governed by one or more signals and includes connections, if any, used by a train when entering or leaving a station or when passing through a station or between lines.
RUNNING TRAIN
: Means a train, which has started under an authority to proceed, and has not completed its journey.
SHUNTING
: Means the movement of a vehicle or vehicles with or without an engine or any other self-propelled vehicle for the purpose of attaching detaching or transfer or for any other purpose.
SPECIAL INSTRUCTIONS
: Means instructions issued from time to time by the authorised officer in respect to particular case, or special circumstances.
STATIONS
: Means any place on a line of Railway at which traffic is dealt with, or at which an authority to proceed is given under the system of working.
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STATION LIMITS
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: Means the portion of a railway, which is under the control of a station master and is situated between the outermost signals of a station or as may be specified by special instructions.
STATION MASTER
: Means the person on duty who is for the time being responsible for the working of the traffic without station limits, and includes any person who is for the time being in independent charge of the working of any signals and responsible for the working of trains under the system of working in force.
STATION SECTION
: Means the section of station limits. 1) At a class ‘B’ station provided with two aspect signals, which is included : a) On a double Line, between Home signal and the Last stop signal of the station in either direction ; OR b) On a single line (i)
Between the shunting limit board or advanced starter’s (if any) or
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(ii)
Between the home signal if there are no shunting limit boards or advanced starters, or
(iii)
Between the outer most facing points, if there are no Home signals
or
Shunting
limit
Boards or Advanced starters. 2). At a class “B” station provided with manually
operated
multiple
aspect
or
modified lower quadrant signals, which is included ; a) On a double line (i)
Between
the
Outer
most
facing points and the last stop signal of the station in either direction, OR (ii)
Between the Block section limit board, where provided, and the last stop signal of the station in either direction
b) On a Single Line (i)
Between the Shunting limit
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Boards or Advanced Starters (if any) OR (ii)
Between the Outermost facing points if there are no shunting limit
board
or
Advanced
starters.
SUBSIDIARY RULE
:Means a special instruction which is subservient to the general rule to which it relates and shall not be at variance with any General Rule.
SYSTEM OF WORKING
:Means the system adopted for the time being for the working of trains on any portion of a railway.
TRACK CIRCUIT
:Means an electrical circuit provided to detect the presence of a vehicle on a portion of a track, the rails of the track forming part of the circuit.
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CONCEPT OF LQ, UQ SIGNALING Semaphore Signals can be displayed in any 4 quadrants. In India we follow left-hand rule. Hence we use L H Quadrant.
In lower quadrant only two aspects 0o and 45o is possible. coincides with post. Hence not useful.
In upper quadrant 3 aspects 0o, 45o and 90o is possible.
3rd position
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Two Aspect Lower Quadrant Signals :
Stop Signals : It is a Semaphore arm – Square ended, painted red with white bar parallel to the square end rear side – white painted with black bar to distinguish approach of signal direction. -
arm at 0o
Night Aspect-
ON Aspect
-
arm at 45o
Red light
Night -
Green light
Stop
Aspect-
Proceed
ON Aspect
G
R
Indication : Stop Dead.
Indication : Proceed.
ON Position
OFF Position
Need for Warner Signal : A stop signal when taken OFF indicated Proceed i.e., he has to proceed till he finds next signal. That means the driver has to keep a continuous watch to locate the aspect of the next signal in advance. This is continuous strain on the part of the driver. It affects the speed of trains and punctuality in case of poor visibility.
It is quite possible the driver may encounter ON aspect
suddenly and unable to stop short of signal. He may overshoot the signal at ON. This is most dangerous situation, and it may cause accident. Hence, there is a need for a Warner signal. Warner signal has a different design of arm, to pre-warn the stop signal ahead.
.
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Warner Signal:
Semaphore arm: Fish tailed end painted red with white bar. In rear painted white with black bar. Warner signal can be located on an independent post or below a stop signal.
ON Independent post:
Fixed Green
Fixed Green
1.5 to 2 Green Red
ON Aspect
-
Arm at 0o
OFF Aspect -
arm at 45o
Aspect
-
Proceed with caution
Aspect
-
Proceed
Indication
-
Proceed with caution &
Indication
-
Proceed
be prepared to stop at next Stop signal. Night aspect -
Red light below fixed Green light
Night aspect -
Greenlight
below fixed Green light. OFF aspect indicates all stop Signals ahead are clear, the Train can run through.
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NOTE : i. A Warner signal must not be capable of being taken OFF for any line other than that over which the highest speed is permitted. ii. Until all the relevant signals have assumed OFF aspect that means, Permission to enter in to next block section is also taken. iii. Even if any one of the Stop signals ahead is ON the Warner should not display OFF aspect.
Warner below a Stop Signal :
Under certain circumstances, a Semaphore Warner is required to be place on the same post of a stop signal. Then the fixed green light is dispensed with.
There are three indication to the Drivers : Aspect : Stop
Proceed with Caution
Proceed
Indication :
Proceed with Caution and
Proceed. Block
be prepared to stop at the
section ahead is
next stop signal
clear.
Stop Dead
Pre-warning to the driver of an approaching train can be given only when a Warner signal is placed on a post by itself. In the case of Warner Signal placed below a stop signal, no pre-warning is available for the Stop signal. In both the cases, Warner signal taken OFF indicates “Run Through” condition – All signals ahead taken OFF. Pre-warning of all stop signals is only possible with MAUQ signaling.
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Multiple Aspect Upper Quadrant Signaling :
Stop Signal : Semaphore arm square ended arm painted red with white bar in front. Painted white with black bar in rear.
ON Position
OFF Position
Red
Y
G
Aspect : Stop
Caution
Proceed
Indication : Stop Dead
Proceed and be
Proceed
Prepared to stop at next stop signal.
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The second yellow light is visible only in 450 position. It is not to be visible in any other position (00 and 900 position). A mechanical arrangement is made to blank out the signal (yellow aspect) in any position other than 450 aspect.
ON Position
OFF Position
Y
Y
Caution
Attention
G
Proceed
Permissive Signals and Absolute signals : Warner signals in Two aspect and Distant signal in Multiple aspect are not stop signals. They permit approaching driver to pass these signals in ON position. Hence they are called Permissive signals.
The Stop signals in 2 aspect and Multiple aspect can not be passed at ON unless and until they are specially authorised by the SM or the signal is changed to OFF position. Hence they are called Absolute Signals.
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Distant Signal :
The further most signal at a station and first signal approached by an incoming train is the distant signal in multiple aspect upper quadrant signaling. Arm is fish tailed painted yellow with black bar parallel to fish tail. painted white with black bar.
Night -
ON position - Yellow light 45o Position - Two Yellow lights, one below the other. 90o Position - Green light.
Rear
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Colour Light Signals Due to the following advantages Colour Light Signals are used instead of Semaphore Signals. •
In Colour Light Signals both day and night aspects are the same – avoids confusion to drives
•
Signals have longer range of visibility – especially during night.
•
No Mechanical Moving parts – Easy to maintain.
•
Not limited due to range of operation, as in mechanical signals
•
Improved reliability of signals
•
Improves punctuality.
M A C L S – 3 Aspect – Stop Signal
ON Position Aspect : Stop
OFF Position Caution
Proceed
G Y R
Indication : Stop Dead
Proceed and be Prepared to stop at Next stop signal
Proceed
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ON Position
24
OFF Position
G Y
Y
R
Aspect : Stop Indication : Stop Dead
Caution Proceed and be
Attention Proceed and be
Prepared to stop at prepared to pass next stop signal.
next stop signal at Restricted speed
Proceed Proceed
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M A C L S – 4 Aspect Stop Signal M A C L S – 3 Aspect – Distant Signal ON Position
OFF Position
Y
Y
Y
Y
P
P
Caution
P
Attention
Proceed
C L S – 2 Aspect – Stop Signal ON Position
Stop
OFF Position
Proceed
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Warner – ON a post by itself ON Position
OFF Position
Fixed Green
Fixed Green
G R P
P
Aspect – Proceed with caution
Proceed
Indication – Proceed with caution and be
Proceed
Prepared to stop at the next stop signal Warner below a Stop Signal
G
G
R
ON Position
OFF Position
Aspect : Stop
Proceed with caution
Indication – Stop
Proceed with caution and Proceed Block section ahead be prepared to stop at the next stop signal
Proceed is clear
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DESIGNATION OF SIGNALS Signals are necessary to provide the required space interval between the trains. Signals are necessary to control the entry of trains in to the block sections, into the stations and with in the stations for different purposes. Signals are designated describing the function of the signals.
APPROACH SIGNALS :
Signals provided for receiving a train is known as Approach Signals
HOME SIGNALS
:
Stop signal at the approach of a station. It gives entry to the housing point i.e., station.
Home
Platform
BRACKETED SOME SIGNAL : Where there is more than one line, each line is provided with Home Signal. All such Home signals are bracketed on a common post or a gantry.
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ROUTING SIGNAL : In cases more than one receiving line may be available for different groups. Distance between home and station stop may be longer.
Routing
May have different places for the trains to stop. These are called Routing signals.
OUTER SIGNAL : Where the reception of train is controlled by more than one signal, then the first stop signal (F S S) is called the Outer Signal and the second stop signal, Home signal.
Home
Outer
An outer signal can also be placed above a Warner signal on the same post.
Warner
Y Outer
Home
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PERMISSIVE SIGNAL : Warner/ Distant There may be additional one or more permissive signals to pre-warn the presence of a stop signal. in two aspect signals, we have Warner signals on independent posts.
Warne
∨
Home
Outer
In multiple aspect signaling, we have distant signals. Distant
Home
∨
In case more than one distant signal is used, the second one as approached by driver is called Inner Distant (Provided in some multiple aspect signaling sections). Distant
Inner Distant
Home
DISPATCH SIGNALS Signals are also provided to control departure of trains. The signals authorize the drivers to start the train and also enter into next block section. If only one departure signal is provided, they are called Starter signals, they also control the entry in to next block section. Starter (LSS)
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If more than one stop signal controls the movement of trains to start and enter into next block sections, then the last stop signal is called ADVANCED STARTER signal which controls the entry in to next block section other Starter signals are provided near the fouling marks. Starter
Advanced Starter
Starter
In some stations, more than one-dispatch signals are provided and this signal between starter and advanced starter is called Intermediate starter signal.
LSS
LSS
Starters
Intermediate Starters
OVERLAPS Overlaps are referred to as adequate distance. Block Over Lap (B O L) : It is the extra length of track in advance of the first stop signal of a station, which must be kept clear, before Line clear can be given to the station in rear.
Signal Over Lap (S O L) : The length of track in advance of Stop Signal, which must be kept clear before the signal next in rear could be taken OFF.
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Two aspects
B O L : 400 Mts.,
S O L : 180 Mts.,
Multi aspects
B O L : 180 Mts.,
S O L : 120 Mts.,
For Automatic Block Signaling – BOL/SOL – 120 Mts. By increasing the number of aspects, Overlaps can be reduced without sacrificing Safety because signal aspects can be repeated by signals in rear in a rational manner.
BRAKING DISTANCE :
The distance traveled by a train after its brakes are applied is known as Braking distance. There are two methods of Application of Brakes : ¾ Normal Service application ¾ Emergent application including setting in reverse.
Braking distance depends on : (i)
Speed
(ii)
Brake power available
(iii)
Gradient
(iv)
Rollability of wheels
(v)
State of rails, curvelence of track
(vi)
Wind velocity, weather condition (dry or wet)
(vii)
Type of train
(viii)
Load of train
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After all tests, it is now decided that for a full load passenger train on level of gradient at 65 kmph, the braking distance is 1 km approximately.
SIGHTING DISTANCE :
The distance over which the most restrictive aspect of a signal is visible from the driving compartment of an approaching train under normal condition of visibility.
REACTION DISTANCE :
It is the distance traveled at the permissible speed during the time taken by the driver to react to the aspect of signals.
Minimum Sighting Distance = NBD + RD
Sighting distance is an uncertain factor – In two aspect signaling – signals are not pre-warned. In multiple aspect all signals are pre-warned by aspects of signals in advance.
PRESCRIBED SIGHTING DISTANCE :
TWO ASPECT : Outer – 1200 Mts. Where section speed is 100 kmph and above Warner : (on independent post) – 400 Mts.
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Home - 400 Mts. Main Starter – 400 Mts. All other Signals – 200 Mts.
MULTIPLE ASPECT :
Distant – 400 Mts. Inner distant – 200 Mts. All stop signals – 200 Mts. Where not possible to have continuous visibility as above, speed of trains is to be suitably restricted.
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LOCATION OF SIGNALS Signals are normally located on to the left side of the track. However, for better visibility a signal may be located on the right side also.
Two Aspect Homes : Should be located close to first set of facing points clear of lock bar. If it is necessary to increase the distance between the Home and Facing points beyond 180 Mts. Other arrangements should be made for holding the route.
Multi Aspect Homes : Should be located at 300 Mts. Is (180 + 120 Mts.) from the first facing points. Facility for shunting in face of approaching if provided, the home may be shifted outward. So that block overlap is available between the home and opposing advance starter or shunting limit board. On double line, Home may be located at 180 Mts. in rear of facing point or Block section limit board.
Starter Signals : Should be located at the leaving end fouling marks or lines in the case of parallel lines at distance exceeding train length from the signal in rear. The distance between the homes and starting should not be less than 400 Mts. In the case of LQ signaling and 180 Mts. in case of Multi aspect Signaling. An alternative location is signal overlap in rear of fouling mark. This provides more operational advantages.
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Advanced Starter : On single line at 180 Mts. from Outer most trailing point. The distance may be increased if required, provided the opposing outer in ‘B’ class station, the home in MAUQ as the case may be can be located at a distance of at least block overlap from the adv. Starter. On double line it should be placed at full train length plus signal overlap in advance in Starter signals.
But in the
present practice the advance starter signals are being located at 120 Mts. from Outer most trailing points.
Outer : On single line at 580 Mts., between Outer home (so that the BOL & SOL for an opposing train being received at stations is available). Where there is an advance starter or SLB; it should be ensured that block overlap of 400 Mts. is available between it and opposing outer. On double line, a distance of 400 Mts. should be provided between it and corresponding home.
Warner / Distant : These signals are located at normal braking distance plus reaction distance in rear of the stop signals in advance of them.
Where it is not possible to
provide normal braking distance at least emergency braking distance equal to 1 km to be provided.
Double Distant : In accordance with GR 3.07(6) two distant signals (Distant signal and Inner distant signal) have been provided in some multiple aspect signaling sections.
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The second distant signal is generally placed at a distance of 2 Kms from the first stop signal eliminating Warning Board.
The meanings of the aspects of these signals are as under : Indication to Distant Driver Signal
Inner Distant
Home Signal
May stop at
Yellow
Red
Double
Home May stop at
Main line Starter
Adv Starter
-
-
Red
-
Yellow Green
Double
Yellow
Main line starter
Yellow
To Run through Green
Green
Green
Green
To stop at Loop
Double
Double
Yellow
Starter or Pass
Yellow
Yellow
with route
Via loop
Green
Indicator.
Subsidiary Signals : Subsidiary signals are those signals, which control the movement of trains with in the station section. Shunt Signals : 1) Authorize movement only at such a slow speed, so as to be able to stop short of obstruction and Control shunting movements. 2) Shunt signals, when taken OFF, authorizes the driver to draw ahead even though Stop signal above it is at ON. Shunt signals can be a Disc type, Position light; Miniature arm type (under spl. Instructions)
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Disc type : Circular disc painted white with red horizontal bar in the front and white with black bar in rear.
ON Position
OFF Position
R Red
LQ Green
R
UQ R Yellow
Red
R
Aspect: Stop
Aspect: Proceed slow
Indication: Stop Dead.
Indication: Proceed with caution for shunting
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Position light : Position light shunt signals are considered on Colour Light Signals. They are same both for two aspect of Multiple aspect; LQ or UQ day and night aspects are the same. ON aspect
OFF aspect
Two lights Horizontal
Two lights inclined
White Light
White Light
Miniature Semaphore type : Arm Square ended. Painted with Red with white bar provision of this signal only under special instructions. ON Position
OFF Position OFF
ON
G R LQ
R
UQ
Y
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Calling ON Signal : Always provided below a Stop signal. Generally for the approach of a train. It is taken OFF when the main stop signal has failed (unable to be taken OFF) should be taken OFF only after the train has come to stop.
Callings on
Signals are two types. 1)
Miniature arm type : Arm Square ended painted white with Red bar in the front while with black bar in the rear
ON Position
OFF Position
UQ R
RED
R R
No-Light
ON Position
Y
OFF Position
LQ
Red
No Light
Red
Yellow
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2)
Colour Light Type : marker plate.
40
Colour light type are provided with C
Under approved special instructions, calling on
Signal can be provided below a stop signal, except LSS. ON Position
OFF Position
NO LIGHT
C
.
MINIATURE YELLOW LIGHT
C
Repeating Signals : Repeating Signals are used. 1) When ever minimum visibility is not available for a fixed signal 2) To inform the driver about the condition of the main signal in advance. They are provided with R marker and are required only for two aspect signals (In MA all signals are pre-warned).
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Types of repeating signals are : Square ended Semaphore arm type : Painted yellow with black bar in the front painted white with black bar in rear. ON Position
OFF Position
R
R
Banner type : Disc painted whited back ground.
A yellow rectangular arms with black
boarders at the top and bottom. It rotates on a central pivot it takes 45o position in LQ, when main signal is taken OFF. It is not lit during nighttime. ON Position
OFF Position
Y Y
R
R
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42
Colour Light Type : It is generally provided in 2 aspect CLS. ON Position
R
Signal with it repeats is at ‘on’
OFF Position
R
Signal with it repeats is at ‘off’
Co-acting Signals : All the fixed signals must have a minimum visibility to the driver and be continuously visible to the driver. When it is not possible to have continuous visibility due to foot over bridges or tunnels or any other obstruction, co-acting signals are provided. Co-acting signals are duplicate signals fixed below running signals on the same post at such a height that either main signal or co-acting signal is visible. Main signal and co-acting signals are rigidly connected. They work together.
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Markers provided on the Signal post : P marker for permissive signals
P
P letter in black on white disc fixed between the signal
C marker for calling ON signal
C
C letter in black on white disc
R marker for repeating signal
R
R letter in black on white disc
G marker for Gate stop signal
G
G letter in black on Yellow disc
IB marker for intermediate BLOCK IB IB letter in black on white disc Stop Signal Repeating Signal in CLS territory R
R white illuminated against black back ground
A marker on automatic stop signal A
A letter in black on white disc
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A marker lit on Semi automatic
44
A
Signal
A lit on black back ground disc When working as automatic mode. A extinguishes when working in manual mode
Indicators: Point indicators (target type) Points set straight Day
Night WHITE LIGHT
WHITE TARGET POINTS SET FOR TURNOUT
EDGE OF TARGET
GREEN LIGHT TARGET TYPE
DAY
TRAP
OPEN
NIGHT
OPEN
CLOSE
CLOSE
RED TARGET
GOODS RINGS ON SIGNALS TO READ GOODS LINE
INDICATORS
RED TARGET
EDGE OF TARGET
.
R DOCK PLATFORM SIGNALS
.
R
GREEN LIGHT
SIGNAL NOT IN USE
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45
Indication Boards : Shunting Limit Board : Provided on single line. To distinguish limit up to which shunting can be performed in the face of an approaching train. A black across on yellow back ground. Temporary lit during night. Visible from both sides. Fixed on a post-painted white and black alternately.
Shunting Limit Board
Block Section Limit Board : Provided on multiple aspect double line territory only. Provided where there are no facing points or when the outer most facing points at the approaching end is a trailing point. A black cross on yellow back ground. Temporary lit during night, visible from both sides. Fixed on a post painted white and black alternately.
BLOCK SECTION LIMIT BOARD
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46
S Marker Provided at an intermediate siding taking OFF from main line. Provided in the facing direction. A circular board with black letter S on yellow back ground.
S S S
Warning Board : Provided in rear of first stop signal or gate stop signal at a minimum distance of 1400 Mts. place left side of line to which it refers. To give an indication to driver that he is to be on the look out for stop signals. Where double distant is provided Warning Board is dispensed with
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Indication boards are also provided to give warning to the driver about change in type of signaling or block working etc. The board will have suitable legend like “ENTERING TOKEN TERRITORY” “ENTERING TOKENLESS TERRITORY” “ENTERING AUTOMATIC BLOCK TERRITORY”
ISOLATION : The term Isolation denotes the condition in which line for a particular movement is separated from all adjoining line connected to it in such a manner that the isolated lines cannot be fouled or interfered with by any movement-taking place on the adjoining lines.
Rules regarding Isolation : 1) A line which train movements at speeds higher than 50 kmph are permitted, the line should be isolated from all connected lines. 2) Passenger lines should be isolated from all connected lines and sidings, what ever the speed may be. 3) Isolation of goods reception lines from sidings is considered desirable 4) To maintain safety in thorough running, points and trap sidings should not be inserted in the main or through lines. Exceptions to this rule, may be adopted with the special sanction of CRS is obtained are :
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48
i. Where other means cannot be adopted, to permit simultaneous reception of trains on single line sections. ii. To trap vehicles running away from a station iii. To avoid trains entering from block section due to heavy falling gradient. Methods of Isolation : 1) Connecting to another line or a siding Siding
Loop Main
2) Provision of short dead end sliding (Vehicles should not be stabled on this siding). Loop
Siding
Main
3) Provision of traps, derailing switches (inexpensive, popular dependable) Loop
TRAP
MAIN
4) Long dead end siding with trap (Vehicles can be stabled on this siding) Loop
Trap
SDG
Main
5) Provision of sand humps. Loop
Main
Sand Hump
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Slip Sidings and Catch sidings : For all gauges the maximum gradient permitted are 1 : 400, where as 1 : 1200 is usually allowed with in the station yard. No station yard should be steeper than 1 : 260 except due to geographic conditions, where such a gradient can not be avoided with in the station yard, CRS condonation has to be obtained and special arrangements like “Slip Sliding” has to be provided. Slip Sdg
Block Section
1 : 250
Slip Sdg
Slip Sliding due to gradient steeper than 1 : 100 falling away from the station in the close neighborhood.
SLIP Sliding
Block section L 1:90
If the gradient is steeper than 1 : 80 falling towards the station. Arrangement of Catch siding is to be provided. It is to trap vehicles coming uncontrolled from the block section and trying to enter into the station.
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50
CATCH Sdg
Block section 1:75
1: 75
L
Catch siding due to falling gradient while approaching the station if steeper than 1 : 80. Slip Sliding and Catch Siding points must be interlocked with the block instruments and such sidings should not be used for shunting or stabling purposes.
Simultaneous Reception and Dispatch of Trains : Taking OFF at the same time, of all signals pertaining to the reception of two or more trains approaching a station at the same time is called simultaneous reception.
Advantages : In single line section, track/section capacity will increase, if at all the stations, such facilities are made available. In double line, one train can be started from one line, while another train can be signaled to be received on another line.
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Methods of Providing Simultaneous Reception Facility : 1) In double line sand humps may be provided replacing traps.
loop
DN main
UP main
loop
2) Provision of sand humps on single section
Maximum flexibility but expensive
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52
3) Provision of two sand humps
Economical but platform facility may not be available for passenger train in one direction 4) Extending loops to have signal overlaps on reception lines beyond starter
SOL
SOL
SOL
SOL
5) By providing calling on signal (after trains come to a stop at FSS).
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CLASSIFICATION OF STATION AND MINIMUM EQUIPMENT REQUIRED AT EACH CLASS OF STATION Irrespective of the system of working in force the stations are classified as block station and non-block stations.
Station : Means any place on a line of railway at which traffic is dealt with, or at which an authority to proceed is given to the driver of the train under the system of working.
Block stations : Block stations are those at which driver must obtain an authority to proceed under the system of working to enter the block section with his train.
Non-Block station : These are outlets opened for commercial purpose and no block working is carried here. To cope up with different working conditions stations are categorized in to various classes.
Class A Station : Where line clear may not be given for a train unless the line on which it is intended to receive the train is clear for at least 400 Mts., beyond the Home signal or up to the starter.
Class B Station : Where line clear may be given for a train before the line has been cleared for the reception of the train with in the station section.
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54
Class C Station : At which no train is booked to stop. This includes IBS, line clear may not be given for a train, unless the whole of the last proceeding train has passed complete at least 400 Mts. beyond the Home signal and is continuing its journey.
Class D Station : Situated between two consecutive block stations and do not form the boundary of any block section.
Minimum signaling equipment required for each class of station
Class of Station
Minimum Equipment
Additional Equipment
Two Aspect
Warner, Home, Starter
A Class
Under approved Special instruction, Outer, Warner behind outer.
B Class
Outer, Home
Starter on double
(on Single Line)
line, Warner if
Outer, Home, Starter
speed exceeds 50
(On Double Line)
kmph. Adv. Starter or SLB where shunting in the face an approaching train is required.
C Class
Warner, Home
D Class
Non Block Station
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Multiple Aspect B Class
Distant, Home, Starter
Advance starter or SLB where shunting in the face of an approaching train is required. Block section limit board where no points or outer most point is trailing point at the approach end.
C Class
Distant, Home
On Double Line : Starter signals are included in the minimum equipment for A and B class as entry in to next block section is controlled by signal indication above. Warners are provided for high-speed operation to provide the means for adequate interlocking, starter signals are not used in C class working because trains normally do not stop at such stations. In all these types of stations, before permission to approach is given, the line must be clear up to the first stop signal and the adequate distance beyond it.
Standards of Signaling :
Interlocking :
Interlocking can be defined as an arrangement between
points, signal appliances either electrically or mechanically or both to secure the following objectives :
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56
1) It shall not be possible to take OFF signals for a route unless all the points are correctly set and the facing points are locked for the route, including overlap. 2) Once the signals are cleared, it shall not be possible to alter the points on the route unless the signals are put back to ON. 3) Even though the signals are put back to ON, it shall not be possible to alter the points unless the intended movement over such points is completed. 4) It shall not be possible to operate signals leading to conflicting movements. 5) The points and signals can be operated only in a sequence to ensure safety. 6) Where signals are connected through any devices, the signal shall not obey until the conditions for working such devices are fulfilled.
Standards of Interlocking : In the interests of safety, train speeds should depend on the signal and telecommunication equipment provided. standards of interlocking are prescribed.
Zero :
Uninterlocked. Speed up to 15 kmph.
One
:
Standard I for speeds up to 50 kmph.
Two
:
Standard II for speeds up to 75 kmph.
Three :
Standard III for unrestricted speed.
Four
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Minimum Signaling Equipments required at each standard of signaling
Minimum Equipments
ZERO
STD1
STD2
STD3
Points: 1. How gauge is maintained A gauge tie
Plate where –
Steel sleepers-
Are not provided
2. How Operated
May - be
worked –
locally -
From a frame where points and signal levers are grouped.
3. How Locked
Bolt and Colter
A key lock of approved type locking each switch independently
A plunger type of FPL locking each switch independently, which may be hand operated
A Plunge type of FPL worked from the frame.
No Spl. Arrangemen t
Interlocked
With signal.
Lock – bar/track circuit or such other means
5. Switch detection
Not required
A means for – ntly should
Detecting each be provided
Switch independently
6. Lock detection
Not required
Not required
Yes, if plunger is hand operated or is of the economical type
Desirable
1. Isolation of main line
Not required
Not required
Required
Required
2. Isolation of Passenger lines from goods lines and sidings.
Required
Required
Required
Required
Grouping of Levers:
Not required
Signal lever grouped & enable SM -
Should be Signal and point key provided to levers should be lock up frame grouped
Interlocking
NIL
Indirect by means of key lock Warner should interlock trailing points. Direct locking between signal levers.
Indirect interlocking should be extended to all trailing points direct locking between signal levers.
4. How Switches are prevented from being unlocked under a train
Isolation :
Signals Two aspect
Direct between point & signal levers and where there are different locations SMs supervisory control should be provided.
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A Class
Not usually
Adopted
Warner
Home Starter
B Class
Outer, Common Home
Outer, B/Home
Outer; B/Home Warner to be interlocked with block instrument if starter is not provided
Outer; B/Home and Starter
Distant Home starter
Distant Home
MAUQ / MACLS A Class
Not usually - Adopted
MAUQ / MACLS B Class
Distant home
Distant Home
MAUQ / MACLS C Class
Not usually - Adopted
Thus it can be summarized that signaling arrangements provided at a stations should be based on. 1) Compatibility of the signaling equipments with speeds obtaining on the section. 2) Ensuring optimum utilization of line capacity. 3) Efficient and smooth train working with in the station limits. 4) Economical use of man power. 5) Promoting flexibility, safety and reliability in yard operation.
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Even though the existing signaling equipments cater to the above consideration, the arrangements can not be satisfactorily interfaced. With the technology updating programs to user in better and faster train services. Provision of signaling equipments at station should be spelt out in real terms with capacity to absorb the fore seeable changes in the near future with as little alterations, in the signaling arrangements as possible.
Thus in this context a new format has been brought out under M, Chapter VII. Part I of the revised signal engineering manual 1988.
Level Crossing Gates : Level Crossing means the intersection of road with railway track at the same level. Any form of movable barrier capable of being closed across the road traffic at the level crossing is known as level crossing gate.
Level Crossing gates are three types : Single leaf, Double leaf; Lifting barrier. Single and double leaf gates open away from the track. They are locked in succession by E type locks. The lifting barriers when operated for road traffic, it is vertically lifted up and in closed condition it is horizontal across the road traffic. Boom gates are provided in single or double units on each side and are mechanically or power operated.
Classification : Level crossing gates shall be classified as special class, A class B Class C class and D class. The classification shall be settled mutually
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60
by engineering department in consultation with the local government authorities after conducting the railroad traffic census.
Special Class A Class
}
B Class C Class
For Road Vehicles
D Class
For Cattle Crossings.
Location : As far as possible level crossing shall not be located near stations and marshalling yards. If inevitable they shall be located beyond shunting limits in the station yard.
Control and Protection : The working of the level crossing gates with in the stop signals is under the control of the SM and the working of those out side the stop signals is under the control of permanent way department.
TWO ASPECT 1.4 K.M
B:O 400 m
>
G
> MAUQ
1.4 K.M 1 KM B:O 180 m
>
G
>
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Protection of level crossing gates inside the station limits : In the case of level crossing gates inside the station limits of block station worked under absolute block system the stop signals on either side of the level crossings are utilized to function also as gate signals by providing interlocking between them and the level crossing gates.
But if the stop
signals are not available new signals are to be installed for protecting important level crossings.
1.4 K.M
Gate cum Distant Less Than B.D Gate
Distant 1 KM G
180 M
120 M
G 180 M
180 M
1 KM ADV.STR cum GATE DISTANT
Inter Cabin Control Principles of Slotting: The control of signals by more than one source, other than the operating source is called slotting. The source, which releases the slot, is called slotting agency. The source, which actually operates the signal, is called Operating agency.
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Purpose of slotting : 1) To ensure that the points located on the line controlled by the signal including the overlap are set correctly and facing points locked and the line is clear, before the signal is taken OFF.
2) These conditions are maintained until the train movement is completed. In other words no other conflicting or fouling movement is allowed to take place and the points are not altered until the train movement is completed. Because a slotted signal can be replaced to its most restrictive aspect by any one of the slotting agencies.
Extract of SEM.
Para No. 158 : Except where qualified cabin men are employed, the SM must be provided with interlocked mechanical or electrical control over Warner, home and LSS. Para No. 159 : Control of Starters / Advanced starters on single line. At single line stations, where token instruments are used, the advance starter or where there is no advance starter, the starters must be controlled by the block instruments of the corresponding section. Para No. 160 : Control of Starter / Advanced starters on Double Line. At Double Line stations where block instruments are in use the advanced starter or where there is no advanced starter, the starter must be controlled by the L C indication of the block instrument of the corresponding section.
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System of Train Working – Block Working Control Over movement of trains : Basically control over the movements of trains can be achieved by two methods. Time interval method Space interval method
Time Interval Method : Movement of trains can be controlled and adequate interval between two trains in the same direction can be maintained by dispatching the following train with sufficient time interval after the departure of the preceding one. In this system, safety is not fully ensured. Since the driver has to ensure that the earlier train is moving forward and proceedings without stopping. This is a definite strain on the drivers he has to keep a continuous watch over the earlier train to avoid collision. Further this is not practicable in respect of Railways due to -
Different types of trains, viz., Goods, Passengers, Express trains.
-
Different types of Powers / Locomotives.
-
Different speeds of trains.
-
Different haulage capacity of trains.
-
Different braking capacity of locomotives.
-
Different terrain.
-
Different loads of trains.
-
Different stoppages.
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64
Space Interval System is one in which, in to a given length of track only one train at a time is permitted to enter. Second on subsequent train is permitted to enter the same length of track, from one of the two sides, only after the first train has cleared the said track. ¾ This ensures safety ¾ Length of the track is divided into sections called Block Section. ¾ At the end of each Block section, there is a Block Section. ¾ Entry into each Block section is controlled through electrical block instruments and is protected by signals. ¾ Information is conveyed to the driver to proceed or stop by signals. ¾ The object of the Space Interval system is to preserve a definite interval of space between trains running on the same line.
Systems of Block Working : To maintain space interval, for safe running of trains, in Indian Railways, six systems of train working are adopted. They are : 1. Absolutely Block System 2. Automatic Block System
Normally used
3. Following train System 4. Pilot Guard System 5. Train staff & Ticket System.
Used only with permission of Rly. Board
6. One train only System Absolute Block System : Essential requirements (as per para 8.01 of GR). a) No train shall be allowed to leave a block station unless line clear has been received from the block station in advance.
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65
b) On double line such line clear shall not be given unless the line is clear not only up to the first stop signal at the block station at which such line clear is given but also for an adequate distance beyond it. c) On single line such line clear shall; not be given unless the line is clear of such trains running in the same direction not only up to the first stop signal at the block station at which such line clear is given but also for an adequate distance beyond it and is clear off trains running in the direction towards the block station to which such line clear is given. This adequate distance is the block overlap which shall not be less than 400 meters in LQ / two aspect signaling / two aspect CLS 180 meters in UQ / multiple aspect signaling or modified LQ signaling. Any reduction to this block overlap requires specific sanction of CRS (under approved special instructions).
STN. ‘B’ STN ‘A’
LSS OF STN.A
FSS OF STN.B
Block Section to be Adequate kept clear Distance
Before granting Line Clear SM should ensure that -
the whole of the last preceding train has arrived completely
-
all the necessary signals have been put back to ON position behind the said train.
Complete arrival of the train is checked by
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-
physical verification with LV board / tail lamp
-
provision of last vehicle check device.
-
Continuous track circuits.
-
Axle counters, etc.
Ensuring signals put back to ON is done by -
providing reverses on mechanically operated Semaphore signals.
-
Through arm type circuit controllers, relays etc.
-
In case of colour light signals through relays.
-
By treadles or track circuits.
Automatic block system on double line : Essentials of Automatic Block System : 1. Provision of continuous track circuits or axle counters 2. Line between two stations is divided into a series of sections known as automatic block signaling sections. 3. Entry into each block section is protected by a Colour light stop signal. 4. Track circuits/axle counters should control the aspects of such signals. -
It cannot display yellow aspect – unless one block section and overlap are clear.
-
Double yellow aspect - unless two block sections and overlap are clear.
-
Green aspect – unless three block sections and overlap are clear.
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-
67
Signal is replaced to ON automatically soon after the passage of the train.
5. Where three aspect signals are provided double yellow (second yellow provided on the top) is dispensed with. 6. ‘A’ markers are provided below the colour light signals.
I >
Overlap
I > Berthing track
Overlap
Block Section
Overlap
Overlap
I >
Overlap
Overlap
Block Section
Block Section
I >
I>
I>
I >
Overlap
I>
Overlap
Block Section
Manual & Semi-automatic signals : ¾ Manual controls can be introduced for any special purpose. They are then called Manual signals. ¾ Manual controls introduced or removed at are known as Semi-automatic signals. ¾ They can be worked either as automatic mode or manual mode.
‘A’ Marker signals : Under normal circumstances, there is no need to distinguish between manual, automatic or semi-automatic signals. In case of failure procedure for passing of manual signal is different from passing signals at ON in automatic territory. •
In manual signaling – authority to pass the signal at ON is required to be given to the driver of the train to pass.
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•
In case of automatic signaling – there are no stations and SM to give such authority to proceed. Hence, there is a different procedure for passing such signals at ON.
Procedure for passing signals at ON in automatic signaling : 1. The driver has to bring the train to a dead stop. 2. Then, wait for one minute by day and two minutes by night. 3. Then, proceed cautiously at such low speed so as to able to stop short of any obstruction at short notice. 4. Only after ensuring that the track ahead is in tact. 5. He should arrange guard or assistant driver to walk ahead with hand signals. The train must resume normal speed after passing the ‘OFF’ aspect of the signal in advance. Since procedures for passing signals at ON is different for automatic and manual signaling modes, it is necessary to inform the driver whether the signals of that particular moment are in automatic mode or manual mode in semi-automatic mode; therefore, ‘A marker lit’ is used in case of automatic mode. If ‘A’ marker extinguishes, then the driver will know that signals are working manually and he will follow the rules regarding manual working for passing signal at ON.
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Gate Signals : Automatic signals interlocked with level crossing gates are distinguished by the provision of ‘G’ marker’, yellow enameled disc with a letter ‘G’ in black in addition to an illuminated ‘A’ marker. ‘A’ marker light is lit only if the gates are closed and locked against road traffic.
Procedure for passing the gate signal at ON : With ‘A’ marker light lit – same procedure for an automatic signal displaying the Red aspect. With ‘A’ marker light extinguished -
wait for one minute by day and two minutes by night
-
draw the train continuously ahead and stop of the gate
-
ensure that the gates are locked against road traffic and after getting hand signal from gate man, proceed cautiously up to the signal in advance.
Automatic Block Signaling on Single Line : The main purpose of this system is to increase the section capacity by reducing the headway between two consecutive trains moving in the same direction. The system is particularly suitable in a single line where pattern of traffic is such that trains follow one another in quick succession during certain parts of the day.
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70
Essentials of automatic block system on Single line :
1. The line shall be provided with continuous track circuits or axle counters. 2. The direction of traffic shall be established only after line clear has been obtained from block section in advance. 3. The train shall be started from one block section to another only after the direction of the traffic has been established. 4. It shall not be possible to obtain line clear unless the line is clear not only up to the first stop signal but also for an adequate distance beyond it. 5. The line between two adjacent stations is divided into two or more automatic block signaling sections by provision of stop signals. 6. The movement of trains in automatic block signaling is controlled by automatic stop signals. 7. All stop signals against the direction of the traffic shall be maintained at ON.
Automatic Block Signalling Section
DN
> < Automatic Block Signalling Section
UP
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71
Minimum equipment of fixed signals : -
Manual stop signals at a station Home and Starter.
-
An automatic stop signal in rear of Home signal
-
Additional automatic signals as may be necessary in between block section.
Description of Panel : ¾ A control panel is provided at every station of automatic signaling section. ¾ Each station controls the movements of trains in one adjacent section. ¾ Two illuminated arrows for each direction.
When direction of traffic is
established, arrow gets illuminated White when line is clear. It changes to Red when block section is occupied or due to failure of track circuit / Axle counter. ¾ Signal normal indication to prove that signals of that side of station are at ON. ¾ Permission from (green indication) to indicate pressing of Push button at the controlling section. ¾ Direction switch to establish the direction of traffic. ¾ SMs lock up key – to lock up the panel in the last operated position to prevent unauthorised or inadvertent operation. ¾ Emergency push buttons to permit change of direction of traffic in case of failure of track circuit / axle counter. ¾ Counters (digital) to register each operation of emergency switches.
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Rules for passing the automatic signals at ON : ♦ To bring the train to a stop in rear of signal. ♦ Wait one minute by day and two minutes by night. ♦ Driver to contact the section controller or SM of adjacent block section on telephone near the signal. ♦ To proceed cautiously only after being authorised to pass signal at ON. ♦ If no telephone / telephone has failed, driver to proceed after giving code whistle to guard up to next stop signal in advance. ♦ Be prepared to stop at short of signal.
Following Trains System : Where trains are worked on the following trains system, they may be dispatched from one station to the next following each other in succession in the same direction on the same line in such manner and at such intervals of time as may be prescribed by special instructions. Trains shall not be worked on the following trains system unless the SM of the block station in advance has exchanged messages regarding his readiness to receive the trains and has in addition, given his assurance that no train will be allowed to leave his station for the station from which the following trains are to be dispatched, until the latter have all arrived at his station and until he has received permission to dispatch trains in the opposite direction.
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Pilot guard system : Where trains are worked on the pilot guard system a) A railway servant shall specially deputed to pilot trains; and b) No train shall leave a station except under the personal authority of the pilot guard.
The trains shall not follow one another in the same direction between stations, unless : ♦ The driver has been properly warned of the time of departure of the proceeding train and of the place at which it will next stop. ♦ All the trains are timed to run at the same speed shall not exceed 25 kmph except under special instructions. ♦ An interval of fifteen minutes has elapsed since the departure of the proceeding train.
The train staff and Ticket system : Where trains are worked between two stations on the Train-staff and Ticket system. a) A single Train – staff shall be kept at one of such stations b) No train shall start from either of such stations to the other unless the said Train-staff is at the station from which the train starts and has either been handed to or shown to the driver by the station master when giving such permission.
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Trains shall not follow one another in the same direction between train – staff stations, unless : i. The driver has been properly warned of the time of departure of the preceding train and of the place at which it will next stop. ii. All the trains are timed to run at the same speed, and such speed shall not exceed 25 kmph except under special instructions, and iii. An interval of fifteen minutes has elapsed since the departure of the preceding train.
The One train only system : Trains may be worked on the One train only system, only on short terminal branches on the single line. Where trains are worked on the one train only systems, only one train shall be on the section on which this system in force at one and the same time. A driver shall not take his train into the section unless he is in possession of the authority to proceed.
Control of Outlying sidings: Sidings taking off from running lines and located between block stations known as outlying or intermediate sidings.
Minimum equipment required : Facing Point Lock :A gauge tie plate where steel sleepers are not provided. Facing point lock or equivalent mechanism. Plunger shall lock each switch independently.
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75
Speed Restriction :Speed Restriction of 50 KMPH on running lines over facing point. Where sectional speed is more than 50 kmph S
marker
to be provided. In addition a caution and termination indicator shall also be provided.
Points control through Block Instruments : The points should be controlled through the block system in use only in the case of facing points on the single line as well as in the case of double line trailing points. The points normally set and locked for the running line are released by token / by key interlocking boxes and electrically transmitted keys.
At station X a token key interlocking box with a spare token locked in it and at the siding, a similar box, but with the points key locked in it are provided. An EKT circuit is provided between station X and the siding, a key is locked in the EKT at X and there is no key in the EKT at siding. A train proceeds from X or Y with a token and is stopped at the siding and the token is exchanged for the points key on the token key interlocking box, the points key is used to unlock the points, the train then enters siding. The points are then reset in normal, and after ensuring that the running line is clear, the key is transmitted to X to clear the section. For the train to come out of siding, the guard informs X on the telephone. X obtains a token, exchanges it for the key and transmits the key to the siding.
CAMTECH/S/2001/Basic Concepts/SCR-4
The key is used for unlocking the siding points, the train enters the running line, the points are reset to normal and key released from the points exchanged for the token originally deposited in the token key – interlocking box. The train proceeds with the token to either X or Y.
Disadvantages : Only one train can be dealt with in the siding at a time. On the double line, the block instrument can not be restored to the normal position until the train is received at the receiving end. Interlocking may, however, be provided between the block instrument and the points so that the points can not be unlocked with out the block instruments being in TOL position. When it is necessary to clear the block section, when train has entered the siding, the intermediate siding is worked as block station and switched out when the use of the siding is not required. However, where double line block instruments which provide for an occupation key to enable trains to enter block section in the right direction and return to the same station. The occupation key when removed locks the key in normal position. In such cases, the occupation key can be used for sending trains into intermediate siding and section cleared after the train is berthed in the siding. The train can only return to the station from which it entered into the block section travelling in the wrong
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77
ON SINGLE LINE
50
SIDING
MINIMUM 800 M
RUNNING LINE
T
S
• •
TRAIN LENGTH
30 M
on double line
s
50
SIDING
S
• •
T RUNNING LINE
MINIMUM 800 M
30 M
trailing point on double line
SIDING
S
RUNNING LINES
CAMTECH/S/2001/Basic Concepts/SCR-4
General : To avoid unauthorised interference, all bolts, studs, pins etc of apparatus used for blocking and control of siding points are revetted or otherwise adequately secured. In view of the rule that isolation must be provided, and the isolating traps locked for all movements on the running lines at all outlying sidings. A trap indicator has to be provided but it is not lit during night hours.
Station Working Rules (SWR) : 1. The object of SWR is to regulate safe working of traffic in and between stations depending on the local conditions that exist at the station. 2. The SWR are intended to draw attention of the staff concerned to the rules for giving line clear, taking OFF signals, reception and dispatch of trains, working of level crossing gates, shunting, stabling of vehicles on the running lines, etc. and also instructions regarding working during failure of points , signals, interlocking, communications etc. 3. SWR should be self contained, brief to the point and in unambiguous language. 4. General and subsidiary rules and block working manual rules should not be extracted in SWR. Relevant rule numbers of G & SR, block-working manual may be mentioned. 5. DSO, DSTE and DEE are empowered to issue, modify SWR. 6. SWR should be reviewed once in three years or three amendment slips whichever is earlier.
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CAMTECH/S/2001/Basic Concepts/SCR-4
7. All the staff required to take up independent duties at the stations shall sign a declaration register to the effect that they have read and understood the SWR. 8. Fresh declaration shall be obtained from the staff concerned in the following cases : (a) An amendment is issued to SWR (b) An employee is absent consecutively for more than 15 days. 9. SWR contains twelve paras and six appendices. They are : (a) Signaling Plan (Diagram) (b) Description of station (c) Systems and means of working (d) Systems of signaling and interlocking (e) Telecommunications (f) Trains working (g) Blocking lines (h) Shunting (i) General instructions (j) Visibility test object (k) Essential equipment (l) Names of Fog signal men
Appendices : A
-
Working of level crossing gates
B
-
Systems of signaling and interlocking
C
-
Telecommunications
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CAMTECH/S/2001/Basic Concepts/SCR-4
D
-
Duties of staff
E
-
Essential equipment
F
-
Names of fog signal men
Signaling Plan Taking the operating features in to consideration, engineering department prepares the engineering plan and sends it to S & T department for preparation of signaling plan. Signaling department taking all gradients’ level crossing gates, cabins, etc., prepares signaling plan for arranging signaling equipment. The signaling plan consists of : 1. Permanent way plan along with levels and gradients 2. Types of signals to be provided 3. Location of signals with reference to point or level crossing 4. Classification of station-wise – class A,B,C etc. 5. Standard of interlocking 6. Decide the size of lever frame for operation of each function and also consider for space to be provided to cater for the future. 7. Interlocking plan number 8. Location of cabin … Points, LC gates. After preparing Signaling plan, shall be sent to CRS for approval. The work should be carried out as per approved signaling plan. Any alteration in the signaling plan should not be carried out without the approval of CRS. Signaling plan with IP number should be exhibited at the station’s office, in the cabin of bigger size for instant visibility.
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CAMTECH/S/2001/Basic Concepts/SCR-4
81
DESIGNATION & LOCATION OF FIXED SIGNALS IN TWO ASPECT
LQ SIGNALLING RECEPTION END DESPATCH END
WARNER ON A
HOME
POST BY ITSELF
STATION UP DN
NBD : 1200 M
NOT LESS THAN BOL 400 M TS
BRACKETED HOME
WARNING BOARD
1 KM NBD
UP
WARNER BELOW OUTER
DN
SOL BOL
180 M
400 M
STARTER
WARNING BOARD
OUTER WARNER
HOME
BOL 400 MTS
ADV STARTER
1 KM
STARTER SOL 180 MTS
LSS
CAMTECH/S/2001/Basic Concepts/SCR-4
FOR FIGURE PLEASE CLICK HERE
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CAMTECH/S/2001/Basic Concepts/SCR-4
Question Bank : Subjective : 1. a) Draw a 3-road station B class layout on single line section. Provide signaling arrangement for two-aspect lower quadrant working. b) indicate the block overlap and signal overlap ? 2. what are the conditions for taking OFF Warner signal and for what speed Warner is to be taken OFF ? 3. What are the rules for providing a calling on signal and when it can be taken OFF ? 4. What are subsidiary signals? Give examples ? 5. Explain briefly on isolation, braking distance sighting distance ? 6. Write short notes on any three of the following a) Shunting limit board b) Block section limit board c) Slip and catch siding d) Classification of stations 7. Explain with sketches various markers used in signaling ? 8. What are classification of stations and what are the minimum equipments of signals required for each class ? 9. Write short notes on any three of the following : a) Signal overlap b) Block overlap c) Calling ON signal d) Shunt signal e) Repeating signal
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CAMTECH/S/2001/Basic Concepts/SCR-4
10. Draw a single line B class station with MACLS having simultaneous reception facilities ? Mark all the inter signal distances. 11. Draw a class B 4 road stations with a common loop facility on double line section to standard III interlocking MAUQ signaling and indicate the inter distance ? 12. What is meant by isolation ? What are the rules for isolation ? 13. a) What are the principles of interlocking? b) Write the Minimum equipments to be provided for STD-1 and STD-III interlocking. 14. What are the differences between a shunt signal and calling on signal, distant and Warner signals. 15. Make out a sketch for interlocking on intermediate siding in a single line with out speed restriction and the sectional speed is 100 km. Describe the working of siding. 16. What are essentials of Automatic Block Working 17. Write short note on any four of the following; a)
Illuminated A marker
b)
Co-acting signal
c)
Isolation
d)
Point & trap indicator
e)
Inter-cabin control.
18. What are essentials of Absolute Block System ? 19. What are the requirements of various STDs of interlocking ? 20. Write short notes on any four of the following: a)
Automatic gate signal
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CAMTECH/S/2001/Basic Concepts/SCR-4
b)
Simultaneous reception
c)
Station limit and station section
d)
Station and a block station
e)
Block forward and block back
f)
Running train and train
Objective : Fill in the blanks :
1. The F.S.S in a MACLS Std-III station is __________________________. 2. The maximum speed permitted over the points for straight-line fitted with standard III fittings is _________________________________ . 3. The distance traveled by a train after its brakes are applied is called ___________________________. 4. The distance sufficient to ensure safety is called __________________ . 5. The place at which the railway line across the road is called ____________________. 6. Shunting in the face of an approaching train is permitted at station ________________________. 7. Block overlap at a 3 aspect section is ______________________ 8. What is the meaning of CRS _______________________________ 9. G marker is painted with ____________________ colour background and ______________________________ colour letter. 10. Shunt signals should not be provided on ___________________ signals. 11. CRS means _______________________________________________.
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CAMTECH/S/2001/Basic Concepts/SCR-4
86
12. CSR means _______________________________________________. 13.
Shunt
signal
below
a
stop
signal
when
at
ON
displays
_________________________________. 14.
An independent Warner during night when taken OFF displays two __________________________ lights one below the other.
15. Signal overlap in multiple aspect signaling is ______________________. 16. In two aspect signaling advanced starter is located not less than _______________________ from the top point. 17. Distance between advanced starter and the opposite home signal on single line MAUQ is ___________________________. 18. A calling on signal is provided with ___________________________. 19. When a block station is approached on a steep falling gradient _____________________________ is provided. 20. Normal aspect of distant signal is _________________________. 21. Normal aspect of inner distant signal is _______________________. 22. Minimum visibility for distant signal required is ___________________. 23. In LQ territory block overlap is ______________________________. 24. Calling on signal at ON position display _______________________. 25. The light shown by a point indicator when set to straight line is ________________________ and a trop indicator when it closed _____________________________. 26. The station limits in a MAUQ class B station is demarcated by __________________________ signals. 27. The minimum visibility for all UQ signals is meters.
___________________
CAMTECH/S/2001/Basic Concepts/SCR-4
87
28. A gate cum distance signal will have _____________ number of aspects. 29. The warning board shall normally be fixed at ____________________ meters from FSS. 30. In LQ signaling a gate signal protecting mid section on level crossing gate shall be located minimum ______________________ from the gate.
Choose the Correct Answer :
1. Signal Overlap in Two aspect territory a) 120 Mts.
b) 180 Mts. c) 400 Mts.
[
]
d) 600 Mts.
2. The speed of a train t pass via loop at Std-III interlocking station is a) 15 Kmph
b) 25 Kmph c) 50 d) none
3. Route indicators are treated as a) stop signals
b) signal device
]
[
]
[
]
c) subsidiary d) none
4. A post type CLS shut signal at ON position displays a) 2 light horizontally
[
b) 2 lights inclined at 450 to left c) two lights
5. Isolation of main line from adjoining lines shall be provided if speeds on main lines exceeds a) 15Kmph
b) 50Kmph
b) 300 Mts
]
[
]
[
]
c) 75 Kmph d) none
6. Visibility of man line starter in MACLS is a) 400 Mts
[
c)200 Mts
d) none
7. Maximum equipment of signals at a class A station are a) Outer, Warner, Home
b) Warner, Home, Starter
c) Outer, Home, Starter
d) none
CAMTECH/S/2001/Basic Concepts/SCR-4
88
8. The signal painted with red band is called a) Co-acting signal
[
b) Repeating signal c) calling ON signal d) none
9. A colour light repeating signal when it will display a) Red light
b) Yellow light
[
b) 200 Mts
c) Full breaking
[
]
[
]
d) none
11. In LQ signaling, run through indication is given by a) Home Signal b) Warner Signal
]
c) Miniature Yellow d) none
10. The minimum visibility of an outer signal should be a) 400 Mts
]
c) Advance Starter d) none
12. Isolation of goods reception lines from one another is a) Compulsory b) Desirable c) Not required
[
]
d) None of these
13. The minimum distance between home and outer on double line LQ signaling is a) 580 Mts
[ b) 1 Km
c) 400 Mts
]
d) none
14. The distance signal (where double distance is working in force) is located at
[
a) 1.4 km from home
]
b) 2 km from home c) 1.4 km from inner distant
d) None 15. The first stop signal of class A station a) Outer b) Warner
c) Home
[
]
d) None
16. Minimum distance required between distant and home signal in MAUQ signaling on single line is a) 1400 Mts.
[
]
b) 1000 Mts. c) 1200 Mts. d) None
17. Shunting limit board is provided only in
[
a) Class A station on single line
b) class A station on Double line
c) Class B station on single line
d) None
]
CAMTECH/S/2001/Basic Concepts/SCR-4
89
18. Block section limit board is provided at certain station on
[
a) Double Line section
b) Both single and double line station
c) MAUA territory
d) None of these
19. P marker is provided on
[
a) All distant signals
b) All distant signals in CLS area
c) All permissive signals
d) None
]
]
20. Warner signal located below a stop signal is capable of displaying a) 3 aspects
b) 2 aspects c) 4 aspects d) None
21. Calling ON signal can only be located a) below a stop signal b) below a starter signal
[
]
[
]
c) below a LSS
d) None 22. Shunting in the face of an approaching train up to shunting limit board is permitted in a) Class A
[ b) Class B
c) Class C
]
d) None
23. The adequate distance for an automatic signal to clear in a single line when the next signal in advance in an automatic signal is a) 400 Mts.
b) 180 Mts. c) 120 Mts.
d) AG marker disc.
b) A marker light
]
[
]
d) zero Mts.
24. An automatic stop signal is distinguished by a) A marker disc
[
c) P marker disc
CAMTECH/S/2001/Basic Concepts/SCR-4
90
Say TRUE or FALSE
1. Whenever main home and outer are taken OFF Warner can be taken OFF [
]
2. All distant signals will be fitted with P marker
[
]
3. Warner shall always be fixed below the FSS
[
]
4. S marker is provided at siding taken OFF from running line in block section.
[
]
5. For speeds above 50 kmph and below 75 kmph std-II interlocking shall be provided.
[
]
6. The block overlap in C class station is 180 Mts.
[
]
7. Post type shunt signal will display both ON and OFF aspects
[
]
8. Plunger lock detection is not necessary for STD-III interlocking [
]
9. Calling on signal has no independent location
]
[
10. A catch siding shall be provided at stations where the station is approaching a steep falling gradient
[
]
11. At a class A station line clear shall not be granted for a train of the line is clear up to the home signal.
[
]
12. LSS can be used as shunting signal
[
]
13. A shunting limit board need not be lit during night
[
]
14. Block overlap in BG is more than that in MG
[
]
15. In multiple aspect territory warning board is not necessary when the distant signal is placed at 1 km from the home. 16. Shunting limit boards are provided only on single line
[
]
[
]
CAMTECH/S/2001/Basic Concepts/SCR-4
91
17. In colour light signaling, junction indicator is used so as to avoid speed restriction. 18. A co-acting signal can be located on a separate post by itself
[
]
[
]
19. A point indicator displays a red light during night when the points are set for the turn out.
[
]
20. All block systems required an authority to proceed
[
]
21. B class LCs must normally be kept closed for road traffic
[
]
22. Lock detection is not mandatory in STD-III interlocking when points and lock are worked by separate levers
[
]
23. Generally class A stations are provided with STD-III interlocking only [
]
24. In CLS, junction indicator is used so as to avoid speed restriction. [
Match the following :
[
] 1. Block Overlap
a) 2 aspect
[
] 2. Signal Overlap
b) Isolation
[
] 3. Warner Signal
c) 15 kmph
[
] 4. Repeating Signal
d) Station section
[
] 5. Clamp and Pad Lock
e) On Single Line only
[
] 6. Class B Station
f) Double Line
[
] 7. Trap Siding
g) 120 Mts.
[
] 8. BSLB
h) Calling ON
[
] 9. SLB
i) 400 Mts.
]
CAMTECH/S/2001/Basic Concepts/SCR-4
92
[
] 10. C Marker
j) Station section
[
] 1. Railway Safety
a) Automatic Stop Signal
[
] 2. G Marker
b) Double Line
[
] 3. A. Marker
c) Single Line
[
] 4. H P Lock
d) Sand Hump
[
] 5. P L C
e) Calling on Single
[
] 6. P I C
f) only in two aspect
[
] 7. Isolation
g) CLS distant
[
] 8. No ON aspect
h) Gate signal
[
] 9. A Class station
i) Hand operated point
[
] 10. P Marker
j) CRS
[
] 1. A Class Station
a) Goods line reception
[
] 2. A Marker light
b) Repeater signal
[
] 3. R Marker
c) 400 Mts. form home
[
] 4. Fixed green light over the post
d) Isolation
[
] 5. Outer Signal on double line
e) Semi automatic signal
[
] 6. Visibility of MA Stop Signal
f) Only in T.A
[
] 7. O Marker
g) Warner
[
] 8. Trap Point
h) 400 Mts.
[
] 9. Distant signal proceed aspect
i) 180 Mts. from outermost point
[
] 10. 1st stop signal on double line in MAUQ
j) Received on main line