Can anyone shed any light on this? Plasser Cranes and TRM's have a pneumatic double check valve in the braking system to the brake cylinders. It is listed as part number PC 15917 in the Plasser parts book. It appears even Plasser do not know this number now, We are sure it is either a Knorr Bremse or Westinghouse part. used also on Loco's Trying to find this part for NYMR crane. I appreciate Tampers etc have a similar valve in the braking system that would suffice with a part number that can be sourced, but would like to track down the correct one. Any Ideas please?