Frank:
Check out pipe gone 1557 - the one we made into a rider gon with the chain ends. You wil find trucks with flat bottom bars on one side and angled ones on the other side. Not only that, the trucks have mismatched bars on the same side.
Imagine assembling two trucks with flat bars on on the left side, angled bars on the other. Turn one truck around and put it under the car. Very wierd. I never bothered to notice the side bearings on them though.
1557 was also the car with the interesting railroad name of "Rio Graande".
Must have been a "Monday car" in the Alamosa Shop...