Comeng Brake Unit

Question 1

What are the components of the brake unit?

Answer 1

7 step relay valve (EP brake)
Restricted Application Magnet Valve (M
Cars only)
Variable load valve
Hand release wire
Restricted application limiting valve and ball check valve
Dump valve
Bypass check valve
W.E.P.R triple valve

Question 2

What is the purpose of the 7 step Relay valve

Answer 2

Converts electrical code signals into 7 equal steps of air pressure (EP)
Air comes from MR supply on that car to brake

Question 3

Purpose of Restricted application magnet valve

Answer 3

Prevents simultaneous application of EP braking when on Rheo on M cars only
(A small holding pressure in BC when rheo braking on Westcodes)

Question 4

What is the purpose of the VLV (Variable load Valve)

Answer 4

Monitors air pressure in suspension system, to allow for braking requirements depending on weight on train

Question 5

Purpose of RALV & Ball check valve

Answer 5

Gives us 10% pressure on brake Cylinders (1 on each bogie)

Question 6

Purpose of the Dump Valve

Answer 6

Dumps air from Auxiliary res to release brake (happens automatically)

Question 7

Release ensuring valve

Answer 7

Removes small amount of air pressure (14 kPa) from AUX res in R & R when operating EP brake (ensures triple valve is in released position)

Question 8

Purpose of Bypass check Valve

Answer 8

During EP braking, air passes through the triple valve to BC, but when this cannot occur, Bypass check valve allows MR air to reach brake cylinders

Question 9

Purpose of WEPR triple valve

Answer 9

Controls flow of compressed air from the
- BP to AUX res (to prepare the brake)
- Aux Res to BC (to apply braje)
- B.C. To atmosphere (to release brakes)