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Chapter 7: Essentials of Signalling

Section 1: Signals in General

7.1.1 Multiple Aspect Colour Light Signalling (MACLS) is covered in this chapter.

7.1.2 All signals shall be electrically Lit. The signals shall be free from the possibility
of phantom indication.

7.1.3 All Main signals shall be colour light multi-unit type and shunt signals shall be
of the Position Light type. Calling on signals may be provided as per
Operational needs.

7.1.4 Uniformity of Signalling: It is desirable that;

(a) The signalling at all stations and interlocked level crossing gates in a
section conforms to the same type & standard as per maximum
Permissible speed of the section.
(b) Signalling at a station at either end(s), shall also be uniform as far as
possible.

7.1.5 Signals – Location

(a) The number of signals and their height shall be limited to what is
necessary for Safety and operational requirements.

(b) Signals shall normally be on the left of, or above the line to which they
apply, unless authorized by special instructions to the contrary.
(c) Where signals are erected on right hand side, they shall be provided with
an arrow, pointing towards the applicable line.

(d) Signals shall be so located and aligned so as to;

(i) Display the best possible view of their aspects to Loco Pilot of
approaching trains.

(ii) Avoid, as far as possible the possibility of the aspect of one signal
being mistaken for the aspect of another, and

(iii) Avoid confusion between the lights of Main signals and the lights of
Subsidiary signals or any other lights. The size of lamps/LEDs of
Subsidiary Signals shall be smaller than that of Main signals.
Subsidiary signals shall not be brighter than Main signals.
7.1.6 All equipments shall be so designed, located and secured as to obviate, as
far as possible, any outside interference.

7.1.7 Non-Operational Signal(s) shall be turned away from Track.

Note: (i) when a signal is not in use, it shall be distinguished by two crossed bars
across it, each bar being not less than one metre long and 10 cm wide (GR 3.18)

(ii) Signals not in use, shall not be lit (GR 3.18(3))

Chapter 7: Essentials of Signalling Page 132 of 535