Page 500 - IRSEM_Main Book

21.1.18 Signalling Cables.

(a) Provisions of Chapter 15 of SEM on Cables shall be followed.

(b) At least two cores of cable shall be provided between two ends of the
yard to cater for telephone communication for maintenance purposes in
non RE areas. Where the yard is extending over a large area, the location
boxes may be grouped and one socket may be provided in one of the
location boxes in the group so that telephone communication is
conveniently available for co-ordination with the cabin during maintenance
or rectification of failures of various ground equipments. Where such
groups are situated in different directions from the cabin, a separate pair
of conductors shall be used for each direction connected to the cabin. In
RE area, provision shall be made for telephone communication through a
telecommunication cable if already available or a separate telecom cable
shall be laid for the purpose.

(c) Earth leakage detectors of approved type may be provided to detect any
leakage to earth in cable conductors.

21.1.19 Signals in Outdoor

(a) The main signals shall be of multi unit colour light type. Shunt signals shall
be of position light type. LED signals of approved type shall be used.

(b) Route indicators shall be either of the direction type or multi lamp unit type
or of Stencil type conforming to approved design.
(c) 'A' & ‘AG’ marker lights for semi-automatic signals shall be of approved
type.

21.1.20 Point Machines - Operation

a) The point operating control circuits shall have track circuit control,
overload protection and cross protection.

b) Crank handles with different wards shall be used. The slots in the point
machines provided to take the crank handles would also be suitably made
to take only the crank handle applicable to the group. The crank handles
shall, however, normally be locked. It shall be possible to release them for
use in point machine by releasing a control from the control panel. With
the crank handle released, it shall not be possible to clear the signal for
the concerned routes. The interlocking of crank handle can also be
achieved by using NX key of different wards.

Notes:- (i) For more details of Installation of Outdoor signalling Equipment, Refer to
Chapter 19.

(ii) In case of alterations to existing installations, Detailed documentation for
alterations, duration of Non-Interlocking/Disconnection & sequence of working shall
be made carefully and concerned staff to be briefed.

21.1.21 Various Timers in Signalling circuits shall be as given below in Table-1.

Chapter 21: Relay & Electronic Interlocking Page 446 of 535