Trucks for freight car kits

Weaver trucks are probably your best bet.

It wouldn't hurt to have your Internet address in your profile.  You'll get information directly that a seller may not want on a public forum.

  John in Lansing, IL

Lionel or Atlas 3 rail trucks with couplers would also work.    MTH is a little harder to work with because they mount from the inside of the car.     the Lionel, Weaver, and Atlas all mount from the outside and screw to the bolster.

One thing to think about is to make the bolsters thinner.   As the kits are designed the bolsters are set  up to use Scale trucks and body mount couplers such as Kadees.    The bolsters are the correct thickness to work with scale trucks to set the car at the correct NMRA recommended height for the couplers.    

An option would be to see if you can buy Atlas or Lionel bolsters to go with the trucks.

I have built both Quality Craft and Ye Old Huff and Puff and Labelle kits and they trucks mounted the same way for Scale trucks.    Just find the center of the bolster and drill a mounting hole for a #2 wood screw.   

The height of the bolster and body is important for scale use because it dictates the coupler height.    In 3 rail with talgo mount couplers the truck/coupler is one assembly and defines the height so the height of the underside of the car above rails is only important to appearances.

If you use the Weaver trucks with the hi-rail wheels and coupler bar, the car will be raised about 1/8" to clear the flanges and should work just fine. MTH sells the Weaver trucks now (I don't remember if the couplers come with them, but I have some spares lying around as I'm going the other way).

I leave the bolsters off the car and stack fender washers to the correct height.