Traction Rolling Stock - Indian Railways Institute of Electrical ...

flow measuring gauge, also BP pressure to the driver. Apart from these single pressure gauges
are provided. One single pressure gauge is fitted near the panto reservoir. The second gauge is
provided in the brake pipe line to show the brake pipe pressure. One single pressure gauge is
provided to indicate the pressure in the control side of the VA-lB control valve, which is regulated
by HS-4 control valve.
7.2.12 Other Features
It should be noted that whenever the vacuum setting is done through the vacuum relief
valve (BS), it should be done by seeing the single vacuum gauge fitted in driver's cab.
The first two main reservoirs are provided with auto drain valve and the condensate is
automatically drained off during the "cut out" and "cut-in" cycle of the compressor governor. All the
other three main reservoirs are provided with manual drain cocks to drain off periodically the
condensate collected in the reservoirs.
The main reservoir also supplies compressed air to auxiliaries such as wipers, horns and
sanders. The MR equalising pipe is charged from the main reservoirs through a duplex check
valve set at 5.0 ± 0.1kg/cm².
The main reservoir also supplies compressed air to electrical auxiliaries such as
pantographs, tap changers etc. At the time of initial energisation of loco or when there is
insufficient pressure in pantograph reservoir to raise the pantograph, battery driven auxiliary
compressor is operated to build up pressure in the pantograph reservoir and auxiliary circuit to
energise the loco. The pantograph reservoir is operated against pressure leakage by a diaphragm
operated cock. One safety valve to cut out at 8.5 ± 0.1kg/cm² has been provided to safeguard the
baby compressor from excessive pressure.
7.3 ELECTRO-PNEUMATIC BRAKES
7.3.1 Introduction
All BG EMU stock have been provided with self-lapping electro-pneumatic combined
with automatic compressed air brakes. Two makes of equipment are in use viz. Westinghouse and
Knorr-Bremese (Escort Knor). Though the details of equipment differ appreciably, both systems
are quite similar in principle. The description given below pertains mainly to the Westinghouse
equipment provided in ICF-built EMUs.
7.3.2 Features of Electro-pneumatic brakes
Electro-pneumatic braking is normally employed for service stops. The automatic brakes
are used under the following circumstances:
a) For automatic application of brakes on both halves of a train in the event of a
parting.
b) For application by the Guard in an emergency.
c) For automatic application due to operation of the dead-man's device.
d) For service stops by the Driver in the event of failure of control supply for EP