[1985 kenworth]

yes the trailers do come in various length's and it depends on what you want to build that should determine which trailer kit will be best suited for your application.generally speaking the frame rails for the tamiya trailers are pretty much the same style ,only the length differs.now with the container chassis those frame rails match the frame rails for the tamiya reefer trailer,and of course both of those are tridems(3 axles) or some call them triaxles either way there are 3..the flatbed trailer is the shortest of all not including the pole trailer.and if you really want to go custom you can check out some of the guys in the vendors section on this forum as they build trailers more to scale..hope this helps you out and answers your questions