INDIAN RAILWAYS – MU-2B VALVE

MU-2B VALVE

The MU 2B valve is a two – position valve arranged with a pipe bracket and is used to enable a 28 –  L- 1 Brake equipped unit to be used in multiple unit service with other type equipped units. The  MU – 2B valve pilots not only the F1 selector valve, which is a devise that enables equipment of one locomotive to be controlled by equipment of another, but, also controls the movement of the VA – 1release valve.

The two positions used in the MU – B valve are “LEAD” and  “TRAIL” or “DEAD” the LEAD position main reservoir air piped to port  is connected to port  and thus to the double check valve that leads to the position of the VA- release valve. Independent brake control pressure emanating from the independent brake valve is connect to port  of the MU- B valve through the spool valve and to port . port  20 of the MU – 2B valve connected to the F-1 Selector valve, as well as a double check valve which is in turn connected to the control port of the relay valve and thus provides on independent brake application on the lead locomotive, port 13 & port 3 are connected as a means of providing on the passage to charge in the brake pipe form the automatic brake valve port 30 connected to the F – 1 selector valve provides the connection for a supply of air that position the  F – 1 Selector valve when the locomotive is used as trailing unit.

When the units is used as a trail locomotive, the MU-2 B Valve positioned  in “TRAIL” or “DEAD” position. Ports 2, 3, 13 and 20 are blanked at the MU – 2 B valve. Port 53 is connected to exhaust at the MU-2 B valve, Main reservoir piped to port 63 is connected to port 30 which in turn position the F – 1 selector valve At the  F – 1 selector valve, brake cylinder equalizing pipe air, port 14, is connected to port 16 and 20, both of which are connected through a double check valve and thus to the control port of the relay. This provides a passage for air emanating form the leas during a brake application.