Discussion relating to the PRR, up to 1968. Visit the PRR Technical & Historical Society for more information.
  by eddiebear
About 1940 the Boston and Maine went shopping for used steel suburban (and some mainline) coaches to replace the huge fleet of wooden cars stilll in service. B & M ultimately bought about 400 used steel cars, mostly suburbans, and the largest purchase was over 100 cars from PRR.
One account I've read says these short cars were built as MP54s and came to the B & M that way. While I find it conceivable that these could have been delivered to the B & M as electrics, the B & M would have to do some conversion work to make them compatible with its steam hauled fleet.
Question. Were these initally built as MP54s or were they just plain P54s?
  by rnetzlof
To split a hair (a favorite activity of SPFs) there was not, on the PRR, anything called P54. There may have been prior to 1913, but by the time there were any MP54 cars, all cars of that general design were some subclass of MP54 whether they had motors or not.

There is a collection of PRR passenger car diagrams at:

http://prr.railfan.net/diagrams/PRRdiag ... &sz=sm&fr=

which bears out that claim. Plain MP54 appears to have been just a coach, as was MP54a1. Most other subclasses apper to have had motors.

Long Island Railroad had a class P54 but my understanding is that those were quite noticably different from anything on the PRR's roster.

  by walt
The steam hauled pre-1915 PRR P-54 suburban coaches were only the nucleous of the eventual MP-54 fleet ( ie there were far many more MP-54's than there had been P-54's) According to Paul Carleton's Under Pennsy Wires there were forty three trailer cars, but, as indicated they were also desginated MP-54. There would have been nothing, however, which would have prevented the B&M from simply hauling the cars it obtained with locomotives with the Pans down, or from removing the Pans altogether.