Page 174 - IRSEM_Main Book

7.4.6 Trap Indicators (For Non-Interlocked Trap points)

(a)Trap Indicators shall be provided at all Trap Points on running lines which
are not interlocked with signals, unless the position of trap points is otherwise
proved. Trap indicators shall be of the target type.

Note: Points leading to a short dead end and used solely for the purpose of trapping
the running line or sidings shall be treated as derailing switch.

(b) Indications -
(i) When the Trap Points or derailing switches are open, the Indicator
shall display a red target by day and a red light by night in each
direction
(ii) When the trap Points or derailing switches are closed, the indicator
shall display the edge of the disc by day and a green light by night, in
each direction. At trap points where a green light would give a
misleading indication to a Loco pilot, a white light may be permitted to
indicate trap ‘CLOSED’ position only.
Note: Points and trap Indicators shall be provided with miniature lights and be
placed as close to the ground as possible.

7.4.7 Shunting Permitted Indicator (SPI)

(a) Shunting Permitted indicator may be provided to permit uninterrupted to
and fro movements towards shunting neck or other connected lines.
Shunting Permitted Indicator may be of the Disc or Light type.

(b) Indications of SPI: Day and night indications of the Shunting Permitted
Indicator shall be as follows :

Table-2

Indication when shunting is Indication when shunting is not
permitted in the direction to permitted in the direction to which
which it refers it refers
Type
Night
Day Indication Day Indication Night Indication
Indication

Disc Type Black disc with a Yellow cross Edge of disc No light
yellow cross light
painted on it

Light Type Yellow cross Yellow cross No light No light
light light

(c) Operation of SPI: Shunting permitted Indicator may be operated by a
ground lever/EKT which works in conjunction with a Stop Signal, so that
either the shunting permitted indicator or the associated stop signal can
be taken off at a time.

(d) Sidings shall be so arranged that shunting operations upon them involve
the least possible use of, or obstruction, to running lines.

Chapter 7: Essentials of Signalling Page 143 of 535