What cars are currently being used to haul 53’ trailers? Which companies currently offer these in HO scale?
TTX’s “Long-Runner” flatcars. These are two 89’ flatcars connected by a draw-bar instead of by couplers. Accurail makes models of 89’ flatcars, but you will probably have to buy, or make, a draw-bar and use Microscale decals to decal them. Also, single 89’ flatcars will carry a 53’ trailer.
The Walthers 54’ flatcar might be an option. If you assemble it per instructions the trailer hitch might be too far back on the car to fit a 53’ trailer.
No company (that I am aware of) makes models of the other two types of cars. These are 53’ and 57’ platform spine cars.
Walthers makes/made well cars (I think NSC type) that can haul 53" containers. They also made a well car that can also carry 53" trailers or containers.
I forgot about the well cars with trailer hitches. Athearn’s 56’ well Gunderson container car might have trailer hitches on it.
Also, if you can find some of the Walthers 48’ platform spine-cars, used the collapsed trailer hitches on the E and C units, and put trailers on the A, C, and B (end two and middle) units.