Automatic Two Stage Distributor Valve Type IV (C3W2)

Distributor Valve (C3W) - UIC


The C3W2 distributor is basically a C3W distributor with the “Empty-Load” function added, providing two ranges of brake cylinder pressure.

The maximum pressure of 3.8 bars, laid down by the U.I.C., corresponds to the “Load” condition: a lower pressure corresponds to “Empty”.

U.I.C leaflet 543, section8, lays down a maximum brake weight of 120% while the minimum brake weight lies between 40% & 60% according to vehicle type & operating category.

Since the ratio of axle loads is often of the order of 4:1, between the loaded and empty vehicle, it is almost always necessary to employ a two-stage empty-load equipment.

Based on the C3W distributor, and retaining all its main characteristics, a new equipment is developed designated as C3W2, which provides two different brake cylinder pressures for a given brakepipe pressure drop. This has been approved by the U.I.C.

In order to provide this additional function, the c3w2 distributor includes an additional portion sandwiched between the body & the bottom cover of the C3W, and which includes:

  • An additional diaphragm on the main pipe which is operative in the “Empty” setting.
  • A changeover valve & the additional application and release chokes needed to ensure the application & release timings as laid down by the U.I.C., in both the “Empty” and “Load” settings.”