Page 478 - IRSEM_Main Book

(c) An automatic signal on a double line/single line shall require all tracks to be
clear up to the next signal and an adequate distance beyond, before it can
display 'OFF' position as per Para 20.1.1 (d). In case of Single Line, Direction
of traffic, shall also be established.

(d) LED signals of approved type by RDSO shall be used.

(e) All external circuits shall be provided with double cutting arrangements.

(f) The circuits shall be so designed that, if the lamp of the aspect displayed
fails, the signal shall immediately assume the next restrictive aspect. Also if
a signal which must display red aspect does not do so for any reason
whatsoever, the signal in rear shall display a red aspect.

(g) The circuit for illuminated 'A' marker of a Semi Automatic Signal shall be
such that the 'A' marker lights up only when the signal is working as an
automatic signal.

(h) The circuit for illuminated 'AG' marker where provided shall be such that the
'AG' marker lights up only when the conditions for 'A' Marker to light up are
satisfied except for the level crossing gate which may either be open to road
traffic or may have failed.

(i) The illumination of the 'A' marker shall prove the correct setting and locking
of the points as required and ensures the back-locking of the route. Level
crossing gates, if any, on the route shall be proved closed and locked to the
road traffic.

(j) The relevant information of Automatic Signalling gears in section should be
available/visible at station like Signals Aspects, track status information, Axle
Counter reset information and gate information.

20.2.3 Level Crossings in Auto Section: Please refer to Chapter 14, section 1 of
SEM for working of LC gates, approach locking and audible warning to LC gate
man.

20.2.4 Installations - Misc

(a) Track circuits: Provisions contained in Chapter 17 of SEM shall be adhered to.

(b) Power Supply: Provisions contained in Chapter 16 of SEM shall be adhered to.

(c) Installation in 25 KV AC electrified areas: Provisions contained in Chapter 22
of SEM shall be adhered to.

(d) Installation of Cables: Provisions contained in Chapter 15 of SEM shall be
adhered to.

(e) Extant guidelines on Installation, Testing & Commissioning shall be adhered
to.

Note: An example of Automatic signalling scheme using optical fibre cable(OFC), Multi
Section Digital Axle Counter (MSDAC) and Object Controllers (of Electronic Interlocking)
is given at Annexure: 20-A1 for information.

Chapter 20: Automatic Block Signalling Page 424 of 535