Re: SP Low nose GP-9 Question
Author: Dr Zarkoff
Date: 07-15-2018 - 13:54
> I did find a parts list years ago (can't set my hands on the copy easy) that was a "26" (no suffix) engineer's automatic brake valve. It was the obvious predecessor to the later 26B/C versions. A friend found a very early 26 control valve that had a release built into the cover for the main diaphragm. All information points that it was a transit valve that was applied to several transit/passenger projects, before being adapted/adopted by the freight side.
My WABCo parts catalogue index lists:
26-A, July, 1956
26-B, May, 1965
26-B-1, July, 1968
26-B-1A, Oct, 1967
26-C, Oct, 1967
26-C-1, Oct, 1967
26-S, June, 1956
All are listed in the transit brake valve section, which tends to support what you mention about it being developed for transit use (in the mid-1950s) and later adapted for main line locomotives. Graduated release had the same history: it was developed for traction and transit use and later adapted for main line RRs (in the L triple valve of 1905).