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

7.2 DUAL BRAKE SYSTEM ON ELECTRIC LOCOMOTIVES
WAG/5 and WAP/1 & 3 locomotives manufactured at CLW are fitted with twin pipe dual
brake system. Railway have also converted some WAM/4, WCG/2, locomotive to twin pipe dual
brake system. Dual brake system is designed for hauling stock equipped with either graduated
release type single pipe or twin pipe air brakes or vacuum brakes.
Simple schematic diagram explaining the principle of operation working of dual brake
system, vacuum brake system and charging of main reservoir is attached as
Fig.
7.2.1,7.2.3,7.2.4,7.2.5.
7.2.1 Description of the brake system
The main features of the system as fitted on these locos are-
a) Self lapping type independent brakes on the locomotive, i.e. the brakes on locos
can be applied and released in steps with pressure maintaining feature in all
positions.
b) Braking of air braked passenger/freight trailing stock and at the same time
proportional brake application on locomotive through distributor valve.
c) Braking of air brake passenger/freight trailing stock fitted with graduated
release type of brake equipment and at the same time proportional brake
application on locomotive through distributor valve.
d) Dynamic brake interlock to prevent simultaneous application of automatic air
brakes and dynamic brakes on loco. Automatic application of emergency
brakes on loco and trailing stock in case of failure of dynamic brakes.
e) Multiple unit operations with locos fitted with similar type of brake system.
f) In an emergency, brake pipe and vacuum train pipe can be directly vented
simultaneously by the emergency brake valve provided in front of assistant
driver's seat.
g) Loco brakes can be released independent of the train brakes.
h) Provision for freight/passenger changeover cocks to regulate locomotive air
brake application timings depending upon the type of stock to be operated by
locomotive.
i) Provision for the driver to apply independent brakes on leading loco in MU
operation in case of parting between locomotives.
j) In case of very heavy leakage in the feed pipe or failure of feed pipe inter
coupling equipment, twin pipe brake system on trailing stock can be worked as
single pipe system by simply isolating the feed pipe of trailing stock from
locomotives.
k) Power cut off during emergency brake application.
l) Visual indication on driver's cab through air flow indicator device during train
parting, alarm chain pulling or Guard's emergency brake valve operation or
loco parting while hauling air braked stock.