The prototype is discussed in the Rolling Stock Reference Series – Volume Seven, Santa Fe Open-Top Cars, pages 242-243. Richard Hendrickson wrote the book and also was the consultant with Proto 2000 on the models. Pullman-Standard built 200 of these cars in 1943. General American built another 200 as GA-62s with the only difference being the trucks. The GA-60 came with ASF double truss self -aligning spring-plankless trucks while the GA-62 had Barber stabilized S-2 spring plankless. In 1957 both groups had their slope sheets and side sheathing replaced with steel. Proto also did this rebuilt version of the car for modelers after 1957.
The P2K car is an excellent reproduction of the car. Grabs and brake lines are wire. Lettering is sharp and clear and includes letting on the brake cylinder nearly tucked inside. Critical examination shows that the slope sheets are not shown as wood planks and the cars lack tack boards. The models have towing loops which the prototype did not have. The car weighs 2 oz. far short of the 3.5 ounce NMRA recommendation.
Ed Hawkins had a two-part review of the prototype cars (and Athearn versions) in the December 2000 and April 2001 issues of Railmodel Journal.
Thanks to Steve Sandifer for the review and photos.