I have researched the THREE lengths of the PRR LCL M.S. PHASE ONE box cars:
CAPPilot is correct of where the words "Merchandise Service" are placed on the 40'(X29B) and 50'(X41B) box cars.
The 60'(X40B) box car has the words similar to the 50' car.
And to clear up any wrong info.:
As, Bob pointed out that the MTH PRR LCL M.S. Phase One PS-1 50'(X41B) car is pretty, but not a scale stand-in.
I must point out that though MTH 50'(X41B) PS-1 PRR LCL MS P I is not modeled to the prototypical car, it is, however, the best model close to the prototype car, so far.
Hot Water, the prototype car's body was not that of a PS-1 style, as the MTH model is, but MTH's is close to the 'Real-Deal' PRR LCL M.S. Phase I 50' (X41B) box.
I do not know if PRR used a Pullman Standard car building kit for their prototype 50' LCL M.S. Phase One (X41B) box car, or not.
The reasons I have some interest and idea about the PRR MS P I cars are:
The first reason is that my wife's Maternal family live in Nanticoke, Pa., where the PRR ran through. I had better put this reason, first!!!!!
And the second reason is that the Phase I is a beautiful paint scheme, with its intricate, multi colors.
Ralph