I have an RK Allegheny that has lost a small part, or it might not have been there when I bought it used, and didn't notice missing.
On the trail truck assembly, there are six small pieces that the axles fit in, and mine is missing one allowing an axle to be loose, and fall out.
Piece isn't listed on parts diagram by itself, only the entire truck. At $20.00 it isn't unreasonable, but when I sought assistance from MTH, their reply was that the truck is not available. Picture's not the best but if you can view it enlarged you can see the piece holding the axles.
Anyone out there that might have this fitting, or a rear truck?.