This ppt describes the types of signals used in Indian railway and other railways around the world. They may seem complicated but their applications are fascinating, espesially you will like signals such as detonators which blast (certainly not harmful but they warn the drivers by their blast)

1. RAILWAY
SIGNALLING
Aditi K. Shah
Roll No.: 38

2. SALIENT FEATURES OF IR
• More than 150 years old
• In beginning it was total private ownership
• Now it is owned and managed by the Govt.
Of India.
• Mix of the oldest technology to the latest
state of the art
• Largest employer
• Annual output measured in billions
• Perceived as harbinger of economic
development
• Considered the lifeline of the nation

3. IR’S DAILY TRANSPORT OUTPUT
17 Million Passengers
2 Million Tonnes freight loading
8800 Passenger trains
5900 Freight trains
Thus, IR's trains cover the round-trip
distance between earth and moon,
four times a day !

4. To err is human…
To safeguard against that is
Railway Signalling

5. HISTORY OF RAILWAY SIGNALLING
1825: FIRST RAILWAY LINE FOR GOODS
TRAFFIC WAS OPENED BETWEEN
DARLINGTON TO STOCKTON(U.K.)
UNIFORMED MEN ON HORSESUNIFORMED MEN ON HORSES
GUIDED THE TRAINGUIDED THE TRAIN
1830 : FIRST PASSENGER TRAIN BETWEEN
LIVERPOOL AND MANCHESTER
POLICEMAN WERE POSTED ATPOLICEMAN WERE POSTED AT
FIXED INTERVALSFIXED INTERVALS

6. HISTORY OF RAILWAY SIGNALLING
1838 : POLICEMEN WERE REPLACED BY
FIXED MECHANICAL SIGNALSFIXED MECHANICAL SIGNALS
1853 : FIRST TRAIN SERVICE INTRODUCED
ON INDIAN RAILWAYS,
SEMAPHORE SIGNALS WERE USED.SEMAPHORE SIGNALS WERE USED.

7.  Operating rail traffic, safely, speedily and economically.
 Increasing line capacity.
 Providing systems on safe principles.
 Preventing conflicting movements of trains.
 Ensuring adequate interval of space between following
trains or those which can cross or approach each other’s
path.
SIGNALLING
Signalling is a device by which the movement of the train is
controlled
PURPOSE OF SIGNALLING

8. CLASSIFICATION OF SIGNALS
SIGNALS
FUNCTION PURPOSELOCATION OPERATION
STOP
WARNER
DISC
COLORED
OUTER
HOME
STARTER
ADVANCE
ROUTING
REPEATER
CALL ON
HAND
FIXED
DETONATING

9. CLASSIFICATION OF SIGNALS
Controlling signals
Which are mandatory to
observe for train movement

10. CLASSIFICATION OF SIGNALS
Indicating signals
Correspond to the traffic signs
of highways. Also mandatory to
observe.

11. CLASSIFICATION OF SIGNALS
Warning signals
They provide a pre-hand
warning to the driver
about the controlling
signals ahead. These only
enhance the efficiency
and provide a further
safety caution.

12. STOP SIGNAL
• The normal position of the signal is horizontal
& it can be lowered at an angle of 45o
to 60o
with horizontal by pulling the wire from the
signal cabin. In the horizontal position, the
signal indicates the “danger stop” & it is said
“on position”. When the arm is in inclined
position it indicates “clear-proceed” & is said
in “off-position”.
• In the night, the light of the lamp passing
through the spectacles gives signals. Thus red
light indicates danger and green light
indicates clear.

13. STOP SIGNAL
The length and width of arm vary from
120-167 cm and 23-35 cm respectively
The outer end of the arm is about 2.45 cm
Broader than that of the hinged end
It is placed on the left hand side of the
direction of movement of train
The side of the arm facing the driver is
painted red with white band near the end
The other side is painted white with black
bands
7.67 m

14. SEMAPHORE
Operation Time Position Of Arm Position Of Signal Indication Given
Horizontal Arm ON Stop
Inclined At 60
o
or 45
o
OFF Proceed
Red Light ON Stop
Green Light OFF Proceed
Day Time
Night Time
STOP SIGNAL

15. WARNER SIGNAL
These signals are similar to stop signals with the
exception that at their free end V notch is cut to
distinguish it from stop signals
Signals placed ahead of the stop signals to warn the
driver before entering the station
Warner signals are placed generally at about 540 m
away from the stop signals
SIGNAL INDICATIONS
Inclined Position: Track is clear and driver can
proceed with confidence
Horizontal Position: Deriver can take his train
upto Stop signal cautiously

16. SEMAPHORE AND WARNER SIGNAL
Semaphore and Warner Signals can be placed on same the
pole. Semaphore is placed on top and the Warner at about
2 m below it
SIGNAL INDICATIONS
Both in Horizontal Position: Neither approaching
section nor next block is clear
When Semaphore is inclined and Warner Horizontal
proceed with precaution i.e. section up to station is clear but
not the block beyond.
Both in Inclined Position:
Track is clear and proceed
with confidence
SEMAPHORE
WARNER

17. DISC SIGNAL
These are shunting signals which are used for low speed
movements during shunting operations. They consist of
circular discs with red bands on white background
SIGNAL INDICATIONS
When Red band is Horizontal: Stop
When Red band is Inclined: Proceed

18. COLORED LIGHT SIGNALS
These are automatic signals & give
indications by electric lights both
during the day as well as in night.
The signals are provided with
green, yellow and red light.
These signals are provided with
special lenses & hoods to emit beam
of light which can be visible from a
long distance even during the day.
Proceed
Proceed with
Caution
Stop

19. OPERATIONAL SIGNAL
Fixed.
(a) Semaphore.
(b) Colour light.
Moveable.
(a) HAND SIGNALS. (Such as Flags,
hand lights)
(b) Detonators.
(c) Cabin Signals.

20. OUTER SIGNAL
This is Warner signal for the driver which gives the
indication of the position ahead whether the platform is
clear or not.
A certain distance is required to bring a moving train to
halt. This distance depends upon the speed of the train, its
weight, brake power of the locomotive etc.
Thus the first signal is provided at this distance beyond
the station limit, that is why it is know as outer signal

21. ASS
SSHS
OS
OHS
SIGNALS ACCORDING TO LOCATION
INTERLOCKING STANDARDS
STANDARD-I Applicable for station for train speeds upto 50 kmph
STANDARD-II Applicable for station for train speeds upto 75 kmph
STANDARD-III Applicable for station for unrestrictedspeeds

22. In the inclined or proceed position it indicates that track and
platform is clear and proceed normally without any danger.
In horizontal or stop position it indicates that the driver
must bring his train to halt within 90 m before outer signal
and than proceed to the home signal with caution
OUTER SIGNAL
OS

23. HOME SIGNAL
After the outer signal towards station is a stop signal and
exactly placed at the station limit is called home or stop
signal. Its main function is to protect the stations. The
permission to enter the platform is given by the operation of
this signal. The maximum unprotected distance between the
signal and the point, it is intended to protect is specified as
180 m due to its location at the door of station, it is called
home signal.
HSOHS

24. STARTER SIGNAL
This signal is provided at the forward end of platform and
controls the movement of the train as they leave the station.
It gives permission to the train to leave the platform for next
station. No train can leave the platform unless this signal is
lowered, that is why it is called starter signal. A separate
signal is provided for each line.
SS

25. ADVANCE STARTER SIGNAL
The limit of a station section lies between the home
signal and the advance starter signal. The signal which
allows the train to enter in block section is called advance
starter signal. It is always placed beyond the outer most set
of the point connections.
ASS
SSHSOHS
station section

26. ROUTING SIGNAL
When many branch lines diverge in different directions
from the main line, it is very difficult to provide individual
signal for each line at the divergent point.
In such situations various signals for main line and
branch lines are fixed on the same vertical post. These
signals are called routing signal. Generally signal for main
line is kept higher than those for branch lines

27. REPEATING SIGNAL
When the view of the main signal is obstructed due to
some structures or on curves etc. some signals are used to
repeat the information of the main signal. Such signal are
know as repeating signal.

28. CALLING ON SIGNAL
These signal are similar to semaphore signal, but
they are smaller in size and are fixed on the same post
below the main signals. A calling on signal permits a train
to proceed with caution after the train has been brought to
a halt by the main signal. These are helpful when repair
works are going on.

29. T
H
A
N
K
Y
O
U