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

C3W distributor valve causes output air pressure to be sent to control port 2 of C2 relay valve
through F-l selector valve in loco and in the trailing stock. This causes C2 relay valve of loco
and C3W distributor valve of trailing stock to allow compressed air at same pressure to brake
cylinder and proportionate application of brakes in both loco and trailing stock takes place.
Simultaneously port 10 H5 relay air valve senses the reduction in BP pressure. This
valve actuates, closes exhaust port 13 and connects port 9 to port 11. Main reservoir pressure
from port 9 through port 11 and double check valve (A33) operates the pressure switch (RGEB,
B15) to cause auto regression in the control circuit of the locomotives.
7.2.10.3 Train parting with vacuum brake stock (Ref. fig. 7.2.4)
When train equipped with vacuum brake gets parted the proportionate application of air
brake in the loco and vacuum brake in the stock shall take place. During train parting as the
vacuum in the train pipe falls by 10 to 15 cms it is sensed by VA-1B valve whose port 2 and 6 is
having vacuum train pipe as its signal. The VA-1B valve get actuated and the exhauster is
disconnected from vacuum train pipe also ports 1 and 11 of this valve gets connected. Main
reservoir pressure passes to port 1 after getting reduced to 1.4 to 1.7 kg/cm² by control air valve
HS4. This reduced pressure passes to port 10 of HB5 pipe relay valve. On receipt of this control
pressure, HB5 gets actuated and port 9 (exhaust port) gets closed and port 12 and 11 gets
connected. MR pressure through port 12 passes to double check valve (A33) through port 11 of
HB5 relay valve to pressure actuated switch (RGEB, B15) to start the auto regression control
circuit in the loco.