Re: Retainer Valves, was NPS Steamtown Images - PRR X25 circa 1921


Guy Wilber
 

Bill wrote:

"3.) the Retainer valve in this photo and the low 3/4 shot clearly different that the RV's used in forties and fifties. Anyone know when these changed?"

The four position slow release retainer was adopted as "recommended practice" in 1941. The design was advanced to "Standard" in 1946.

The following excerpts from the 1952 Interchange Rules will enlighten the retainer valve requirements for your 1953 modeling.

1952 AAR Interchange Rule 3:

(a) (2-a) Air brakes. Pressure retaining valves of not less than the former AAR standard three position double spring type, including spring caps designed to prevent distortion of springs, required on all cars built new or rebuilt, and on all cars equipped with "AB" type brakes in place of "K" type brake equipment, between January 1, 1943 and January 1, 1948. From owners.

Note.--It is recommended that when cars built new or rebuilt prior to January 1, 1943, receive Class 1 general repairs, retaining valves meeting above requirements be applied. The AAR Standard or Alternate Standard four position slow release type retaining valves meet the above requirement.

(a) (2c) Air brakes. Pressure retaining valves of not less than the AAR Standard four position slow release type or Alternate Standard four position slow release converted type, required on all cars built new or rebuilt on or after January 1, 1948. From owners.

(a) (2-d) Air brakes. Pressure retaining valves of not less than the former AAR Standard three position double spring type, including spring caps designed to prevent distortion of springs, or AAR Standard four position slow release type, or AAR Alternate Standard four position slow release converted type, required on all cars having "AB" brakes applied in place of "K" type brakes on or after January 1, 1948. From owners.

Guy Wilber
Reno, Nevada

Join main@RealSTMFC.groups.io to automatically receive all group messages.