4,000 of these 48-foot class G22 gondola's were built between 1915 and 1917. The prototype photo of road number 775470 on the right is from the PRR Railfan web site. The PRR Railfan web site has a description of G22 class. Finally, the "PRR Color Guide to Freight and Passenger Equipment, Vol. 3", 2002, Morning Sun Books, Inc., ISBN 1-58248-073-7, on pg 79 has another color photo of this gondola.

The PRR G31 subclass d gondolas were built in January 1952. The PRR had 1200 of the subclass d gondolas, all built by the American Car & Foundry Company's Berwick, PA plant. The roadnumbers ran from 375750 to 376949. These cars were 52-1/2 feet long with steel sides and wooden floors. Prototype references are plentiful for this car. The photo of #375892 on the right here came from the PRR Railfan web site. That site also has a side profile diagram, and additional prototype information. The following books also have photos of this car:
"PRR Color Guide to Freight and Passenger Equipment, Vol. 2 ", 1996, Morning Sun Books, Inc., ISBN 1-878887-55-6, pg 79;
"PRR Color Guide to Freight and Passenger Equipment, Vol. 3", 2002, Morning Sun Books, Inc., ISBN 1-58248-073-7, pg 82;
"American Car & Foundry Company 1899-1999", 1999, Signature Press., ISBN 0-9633791-0-0, pg 234.

I have not found any prototype information on this car yet. The Micro-Trains model is a representation of the car built in October 1948. This pre-owned model came with a load of ballast.