From a Westerfield kit...
The earliest reference to conversion of XL box cars to maintenance of way and crew cars (or camp cars as they were called by the Pennsylvania Railroad) is 1937. Blueprints were issued for standard sets of cars. One set entitled "four car unit for living quarters" included a riding car, two sleeping cars and a kitchen/dining car. Another entitled "four car unit wreck train" included a tool car, cable car, riding/locker car, and commissary car. A third showed wire train cars: a riding car with cupola and pantograph and a tool/material car. These were far from the only variations as photos reveal many others. The details, especially smoke jacks and vents were added from available supplies, resulting in standard cars on which almost nothing was standard. The Westerfield models are based on the blueprints in most cases as the plans reveal the position of internal details making the location of ventilators more precise.
The cars may be divided into two groups based on use and another two based on roof style. Cars used to haul supplies had side doors whereas those used for crew did not. Sound original plug doors were not replaced. However, most cars were resheathed and these received standard wood doors opening to the right. Long vertical grab irons were added to the door and door frame. Cable cars had their doors at opposite corners; all others were centered. All cars except the cable cars had stoves and all crew cars had vents. All cars had end doors, more or less standardized to 26" wide with a four-pane window (there were odd exceptions). The riding and commissary cars had a window in the A end; all others did not. A hinged platform folded down over the coupler to allow walking between cars. Separate steps were leaned on the platform to reach the ground.
Sound flexible metal roofs were not replaced. Replacement roofs were plain mullion Murphy style (again exceptions exist). All crew cars had bulges in the roof which held water tanks. When Murphy roofs were added the side sheathing was extended up to the top of these tanks. On old roofs the car line was not distrubed in most cases but, again, exceptions exist. Therefore, there are two different roof line "lloks" on otherwise identical cars. The Westerfield kits include both types.
Almost all cars had electrical connections on the ends of the cars. Tool and material cars seemed to have a standard small electrical box mounted over the door. Crew cars had a larger box mounted next to the door in various positions. Junction boxes and cables were ung wherever convenient.
The cars earliest conversions were painted freight car (oxide) red on all surfaces. In 1937 colors were changed to gray on wood surfaces of sides and ends, and black for roof, underbody, side sills, end sills and metal fixtures (specifically, all grab irons, ladders, brake wheel and staff, diagonal roof walk and brake stand supports). In 1953 the body and roof color was changed to chrome yellow and shortly thereafter (perhaps a matter of months) the roofs were specified to be painted black. The brake staff was painted yellow below the brake stand, black above;the brake stand supports, yellow. Electrical boxes could be either gray, yellow, black or original metal color, probably due to when they were applied. Electrical wires were black. Car interior walls were ochre with olive green wainscot; floors were red.
Lettering was white when the cars were painted oxide. No photos survive to show details of style and placement. Lettering remained standard from 1937 except on a very fre cars that received Pennsy Gothic in the 1960's. Each car had the roadname and car number in 7" black letters and the type of car in 2" letters stenciled on the side. There were no end reporting marks. Tool and material cars supposedly carried the capacity statement below the car number but this is not always seen in photos.
Most cars were numbered in the 480000 and 490000 series with no apparent system for car type. Typical numbers authenticated from photos are shown below:
Plans for a sleeping car appeared in the September 1966 issue of Model Railroader. While the plan shows a refuse holding tank, no photos have ever shown one. We assume it was a late addition and a rarity. Photos and plans for a riding car converted to a welding shop appeared in the February 1978 issue of Model Railroader. An article on the camp cars appeared in the March 1995 issue of Model Railroading, part of a series on MOW cars prepared by Alan B. Buchan. Numerous photos of the camp cars appear in Sweatland, David R. and Robert J. Yanosey, PRR Color Guide to Freight and Passenger Equipment, Morning Sun Books (1992).