Page 443 - IRSEM_Main Book

(e) The top of sleepers which are to support the point machine are at level and
that surrounding ballast is well tamped to prevent sinking during the
passage of train.

(f) The machine shall be so installed that it is clear of all infringements.

(g) Proper drainage shall be provided to avoid water logging near point area.

(h) Wiring from the point of operation to the location box/apparatus case
nearest to the machine shall be in cable. The cable shall be of appropriate
size to keep the voltage drop minimum. The connection between location
box/apparatus case and point machine shall be through underground cable
adequately protected below track and near point machine, through
GI/RCC/DWC-HDPE pipe of approved type or any other approved means.
It shall be tested for insulation and continuity before bringing into operation.

(i) Crossovers shall be operated by separate point machines, one at each
end. The detection of setting and locking of the points at the two ends of a
crossover shall be connected in series.

(j) Means shall be provided to cut off the motor feed in case of obstruction to
the point movement after a predetermined time lag, based on the type of
point machine used. The point operating control circuits shall have track
circuit control, overload protection and cross protection.

(k) The crank handles shall be provided to facilitate operation of points in case
of failure of point machines. For this purpose, the points in the yard may be
divided into convenient groups and to distinguish particular groups, crank
handles with different wards shall be used. The slots provided, in the point
machines for insertion of the crank handles shall be suitably modified 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.

(l) The excess gap around cable entry to the machine shall be plugged to
avoid rodent entry/water ingress.

19.3.2 Point Machine, Notches, Gaskets, Sealing

(a) Electric Point Machine shall be provided with suitable gaskets and wire
entrances shall be sealed to make them water tight and dust proof. All the
extra openings shall be closed as far as possible.

(b) Locking: Electric Point Machine covers shall be locked. The cover provided
for insertion of crank handle shall also be locked with separate key providing
access only for crank handle and crank handle key.

(c) Notches in Stretcher Blades: Notches/Notch profile of the locking, driving
and detection slides should not be tampered/reconditioned. Worn-out slides
should be replaced with new ones.

Chapter 19: Installation, Testing & Maintenance of Signalling Equipment Page 391 of 535