ok ... I usually use MTL-003 02 047 (MTL-1037-1 (low profile)) ... but it really depends upon the prototype of what you are modelling ... some cars use 100-ton roller-beaing trucks ... but others may use 70-ton ones (3-coil springs vs. 2) most MTL trucks will work with Roundhouse cars ... the only tricky thing can be finding the right bolster pin to hold them in to the frame
MTL trucks with couplers Wes577, I'd suggest the old standard MTL 1000 "bettendorf" trucks for these cars, unless you're modeling the modern era, when the 1035 would be suitable, since you did say "MTL trucks with couplers". :embarassed:
An older car would have the 1000 "short bettendorf" trucks. Newer cars could have newer "roller bearing" trucks. The end of the coupler box should be near the end of the car. If you want the cushion underframe look, try the medium couplers. AFAIK there should be no issues with the truck bolster pin. I'd like to see Athearn offer replacement screws to do this conversion.
I agree with Glen... depending on which look you are trying to capture, go for either the short or mediums... Bettendorf or Roller Bearing depends on the car and date.
The general rule for truck mounted couplers I was told is that the coupler box must stick out past the end of the car to avoid having the top of the trip pin get fouled on the bottom lip of the car on a curve. Watch on box cars, since some have the walkway molded in, and that counts as extra length.
