Page 288 - IRSEM_Main Book

(i) visibility of the portion between fouling marks to block section limit is
obscured from the place of operation; or
(ii) frequent shunting involving main line takes place; or

(iii) Advanced Starter is placed at a distance of full train length beyond the
trailing points.

12.5.7 Where Signals are carried on gantries, left hand signal in each case shall refer to
the left hand line, the second signal from the left shall refer to the next line from
the left and so on. The Signal for the main line shall be placed at a higher level
than the signal or signals referring to the other running line or lines.

12.5.8 Calling-on Signal Semaphore arm: The Semaphore arm of a Calling-on
Signal shall be a short square ended arm. The front of the arm shall be white
with a red bar. The back of the arm shall be white with a black bar. The bars
shall be parallel to the end of the arm.

(a) Day indication-By day, the arm shall be

(i) Horizontal in the 'ON' position;

(ii) 45° to 60° below the horizontal in the 'OFF' position.

(b) Calling-on Signal shall be placed below a Stop Signal governing the approach
of a train. Under approved special instructions, a Calling-on Signal may be
provided below any other Stop Signal except the last Stop Signal.

12.5.9 Shunt Signal

(a) Under special instructions, a shunt Signal may be a miniature Semaphore
arm.

(b) Miniature Semaphore Signal:

(i) The Semaphore arm of a shunt Signal shall be square ended. The front of
the arm shall be red with a white bar. The back of the arm shall be white
with a black bar. The bars shall be parallel to the end of the arm.

(ii) By day the arm of a Stop Signal shall be horizontal in the 'ON' position
and 45° to 60° below the horizontal in the 'OFF' position. By night, the
signal shall display a red light in the 'ON' position and a green light in
the 'OFF' position.

(c) Diverging routes: More than one shunt signal may be placed on the same
post and when so placed, the top most Shunt Signal shall apply to the extreme
left-hand line and the second shunt signal from the top shall apply to the next
line from the left and so on. One shunt Signal with or without a route indicator
may also be provided for a number of diverging routes.

12.5.10 Repeating Signal

(a) A repeating signal is a signal placed in rear of a fixed signal for the
purpose of repeating to the driver of an approaching train aspects of the
fixed signal in advance. It shall be provided with a marker consisting of a
white-enameled disc with letter 'R' in black.

Chapter 12: Installation, Testing & Maintenance of Mechanical Signalling Equipment Page 242 of 535