Page 493 - IRSEM_Main Book

(k) For clearing Calling On signals, proving of track circuits in the route and
overlap are not required. Calling On signal shall detect all the points
including interlocked level crossings in the route, which the main signal
above it detects, except points in the overlap. Stop signal ahead is not
blank is not needed.

(l) For clearing of shunt signals, proving of berthing track circuits, points &
LC gates in overlap, stop signal ahead is not blank is not needed.

(m) A white indication for block control on the last stop signal should be
provided on control panel, where-

(i) Section ahead is worked on Absolute Block System and control
panel and block instrument are placed at different locations.

(ii) Block working is by means of axle counter or track circuit.

21.1.7 Non Route setting Type: (For existing installations & Alterations only. No
new Installations of Non-Route setting type to be provided).

The route setting and clearance of signal shall be with the following
conditions:

(a) The points in the selected route and if required in overlap and isolation
are operated to required position by individual operation of switches or
push buttons in conjunction with group push button.

(b) Operation of entrance exit buttons/switches or one control switch clears
the signal if;

(i) SM's key is In

(ii) The interlocking is free

(c) The points including hand operated points in the route including overlap
and isolation if any, are set, locked and detected.

(d) Other conditions are same as para 21.1.6 (d) to 21.1.6 (m) above

21.1.8 Route Release Circuits

(a) Complete route release including overlap shall be effective only after the
signal governing the route is put back to 'ON' and corresponding route
switch/button has been operated to normalize the route. Automatic route
release by the passage of train and complete release of route through
sequential route release shall be provided.

(b) Where a route has got number of route sections, the circuit shall be so
designed that the route section does not release only by picking up of the
concerned track relay. Same is released only after the next track circuit is
also dropped and picked up, except in case when the last track is a berthing
track. In cases where the route is controlled by single track circuit, the route
release shall be controlled after predetermined time delay.

Chapter 21: Relay & Electronic Interlocking Page 439 of 535