Page 442 - IRSEM_Main Book

(h) The cable entries of the signal unit should be closed properly using cement
to avoid rodent entry.

(i) Signal numbering plate (as per Signalling plan) to be provided with black
letters on white back ground.

19.2.3 Hoods and Back Screens

Hoods of adequate size to counter act the effects of sunrays shall be provided.
Where required, metallic mesh at suitable spacing shall be provided to protect
lenses from outside interference.

19.2.4 Cable Entry

Cables shall be used from the point of operation to the location box/signal unit
and/or location box to the signal unit. Cable shall be protected suitably at the
entry points of location box and signal post.

19.2.5 LED aspect unit consists of a cluster of LEDs in series and parallel combinations.
LEDs in a signal aspect shall be arranged in more than one array, so that in
the event of failure of a single LED, whole unit does not become blank. LEDs
in the arrays shall be so inter leaved so that effect of failure of any array is
spread out equally to maintain uniform visibility. Integrated (with built-in current
regulators) LED signal aspects for regulating the current shall be used. Red/
yellow/green LED aspects shall be used for Main /Subsidiary signals, and lunar
white LEDs shall be used for route indicator.

19.2.6 Same make of LED aspects shall be used at a station/section for ease of
maintenance.

19.2.7 Gaskets and Sealing: All openings shall be gasketted and cable/wire entrance
shall be sealed to make the enclosure water tight, dust-proof and vermin-proof.

19.2.8 Locking: The housing shall be kept locked.

Section 3: Installation of IRS Point Machines

19.3.1 Requirements: Electric Point Machines of approved type shall be used.

(a) Electric Point Machines shall be installed in accordance with approved plans.
Ground fittings of approved design shall be used. Ground connections shall
be thoroughly checked for any crack or improper welded joint. Normally the
machine shall be installed beside the close switch leading to high-speed
movements clear of all infringements. Before installation of the machine, it
shall be ensured that.

(b) The JE/SSE (P.Way) has made all the provisions at the Points as detailed
in para 12.13.2 to 12.13.4 & Annexure: 12-A1 of Chapter 12 of SEM.

(c) The machine has been properly cleaned and lubricated in accordance with
the manufacturer's instructions and is working freely.

(d) Proper alignment and level of connections is maintained between the
machine and the point gears.

Chapter 19: Installation, Testing & Maintenance of Signalling Equipment Page 390 of 535