The document discusses various signaling systems and devices used in train operations to ensure safety and efficiency. It details types of signals such as hand, fixed, and colored signals, along with their operational and functional characteristics. Additionally, it explains the mechanisms for train guidance during shunting and maintenance, as well as specifics on reception and departure signals for train movement.

1. o Systems and devices by which trains are operated efficiently,
tracks are used to maximum extent maintaining the safety of
passengers and goods. Includes use and working of signals and
controlling

2. o Provide for safe and efficient movement of trains
o Ensure safety between two or more approaching or crossing
trains
o Provide for safe and efficient shunting operations
o Guide the trains during repairs and maintenance of the track
o Safeguard the trains at converging junction and give
directional indications.

3. o Operational Characteristics: Detonating, Hand, Fixed signals
o Functional Characteristics: Stop, Warner, shunting, Colored
signals
o Locational Characteristics: Reception (outer, home),
Departure (starter, advanced starter) signals
o Special Characteristics: Repeater, Routing, Calling on, Point
indicator signals

4. o Detonating Signals: when hand or fixed signals are not
visible, detonators are placed on rails, which explode with
loud sound when train passes over them, indicating the
driver to be cautious.
o Hand Signals: colored flags or lights are used to indicate stop
(red), proceed (green) or proceed with caution (yellow).
o Fixed Signals: fixed in position and include semaphore and
warner type. Consist of an arm fixed on vertical post, placed
on LHS of track, facing the direction of movement with
horizontal arm projecting away from the track. Pulled by
levers in signal cabin.

5. o When semaphore arm is
horizontal it is said to be ON
and indicates STOP.
o If lowered to 45o, said to be
OFF and indicates PROCEED
o Colored lights are used during
night hours
o Signal mechanism is such that
if something goes wrong it
will always indicate STOP.
Semaphore arm 1.2 to 1.7 m
White band Spindle
Lamp
Spectacle
Crank rod
counterwt
cam
Lever
Chain Signal Post
Pulley
To signal cabin
G. L.

7. o Similar to semaphore in
shape except for a V notch
at free end. The white band
is also V shaped
o These signals are provided
ahead of ordinary
semaphore signal and warn
about the main signal.
V notch and band
Warner arm
o If warner is ON it means
main signal is also ON. If
warner is OFF it means
proceed cautiously and if
main is also OFF then
proceed further.

10. o Disc signals consisting of a
white disc with horizontal
red band and colored lights
(green and Red)
o Operated by pulling lever
manually.
o Used for shunting
operations in yards
70 cm lever
Green
Glass
Red
glass
Disc
Red
Band
Post

11.  High intensity beam,
colored lights are used.
 Visible at night and day
also
 Working is automatic. If
section ahead is occupied
it gives red indication only.
Three aspects, red, green
and yellow
Hood
Red
Yellow
Green
Post

12. o RS control the reception of trains. Further classified as
o Outer Signal: first reception signal faced by driver while
approaching. Indicates end of block section and start of
station limits
o Home signal: second reception signal faced while
approaching station. Indicates entry into station yard

13. o Control the departure of trains. Faced by driver while leaving
the station. Further type
o Starter Signal: first departure signal faced by driver. Generally
located at the end of platform. Indicates to start the train.
o Advanced starter Signal: second departure signal faced by
driver while leaving station. Placed beyond the outermost set
of switches. Indicates end of station and start of block
section.

15. o Whenever there is obstruction to the sight of main signal due
to bridge, pole, building etc., another signal with a duplicate
arm of smaller size is provided, which repeats the indication
of main signal.
o Routing signal: when no of branches takeoff from main track
it is difficult to place individual signal post for each track at
diverging point, so these signals are combined and placed on
single post with signal for main track at higher level.

16. o Used to call the train waiting beyond
the home signal. Consists of a
smaller arm than semaphore arm
and is placed on home signal post at
lower level.
o PI- used to indicate the position of
points. Rotating box with green and
white color code. Green means
points are set to main, while green
means set to branch track. Used for
shunting op.
Box
Green
Disc
White
Side
view
Front
view