None of the ORER data gives me much to scale off of vertically except the inside height. But at 17", I'm thinking it has a wood floor or maybe some sort of brackets or bracing to hold the containers. What I really need is a pictures that shows one of the containers out of the car so I can see the bracing.
If this car is anything like the SP version, there are good interior photos in my volume on SP flat cars, Vol. 3 of the series, _Southern Pacific Freight Cars_ that was published by Signature Press.