Denny Anspach <danspach@...>
It is a fun project matching up the exact prototype permutation of truck to the exact model, but this can commonly fall afoul of a lot of other priorities, especially if one's cars are intended to be operated at will with expected reliable behavior in a train.
Prototype truck exactness: a description often more apparent than real. To my current knowledge, the only Andrews truck that has the correct overall breadth and sideframe thickness is Accurail, a truck that fortuitously happens to be very finely modeled, and can also run like a ball bearing on ice with the proper wheels. For these reasons, this is my default Andrews truck (recognizing the gazillion different Andrews trucks out there, most of which are grossly overwide, overthick, or roll only like a roller skate in deep sand).
However, for flat and other open cars requiring the weight and lowered center of gravity of metal trucks, my default is the Kadee metal Andrews truck. These too can run well, once the Kadee wheels are deep-sixed and replaced.
AAR trucks of all stripes are subject to the same issues. Once in a while, when a prototype is so esoteric that any permutation would be unacceptable, I just accept the inevitable and drag the car around the layout.
Denny S. Anspach, MD