To further elaborate, the NYC USRA cars that were modified to carry air-activated containers were all from the same lot of USRA steel gons. The differences were that the cars with provision for 6 containers had different side cutouts that the cars with provision for 5 larger containers.
All the containers had the same outside diameter, so that, theoretically, any could be hauled by any of the container gons. The gons were equipped with four curved angle positioning locators on the floor for each container.
The cars equipped to haul 5 containers had a steel floor as-modified for container service. The 1937-era cars with 6 containers had wood floors, at least for a number of years after they were placed in container service.
OT - I last saw air-activated containers in service in 2002 down here in south Texas - Halliburton had a number of 3-container cars (non-removable air-activated containers) that were in oil well cement service. Those cars were built in the late 1950's or early 1960's.
Question - How long were the NYC air activated container cars in service? I think one of the taller containers was on the ground at the AC&F plant in New Jersey about 10 years ago - is it still there?
A. T. Kott