One current ongoing project is working over freight cars, setting them up in two basic categories, “collection” or “layout,” and from there into groups of pre-war, post-war, or 1970s era models that I operate on the layout.

One thing I’d like to do, for looks, is not have so many of the layout cars on Scale-Craft trucks. But over time I have noticed, and the current project confirmed, that some types of S-C cars can only run well on S-C trucks. The hopper cars will only work on S-C trucks, period. But the tank cars run and look great on Schorr trucks. Flat cars I normally set up on HO conversion trucks, as they are hidden from view, with slightly undersized wheels. And then we get to the boxcars, stock cars, and cabooses….

With difficulty you can just barely set them up on Schorr trucks, but really they want to be on standard Scale-Craft trucks with standard wheels. That is certainly how they operate the best.

But why? The answer has to do with the actual size of the Scale-Craft wheelsets. Larger wheelsets tend to rub on the bottom of the car.

Nominally, standard freight trucks have 33″ wheels. Doing the conversions (here) and using my calipers, it turns out that Scale-Craft freight wheelsets are consistent at about 31.5″. I suspect that they had to do this because of the flat floors of these cars, there was not room for a larger wheelset without the car being set up overly tall.

Which brings up the topic of other brands. Lionel wheelsets are large and measure out at 34.5″ (!), but the models are made with plenty of room for them. Schorr freight wheelsets are close, but also somewhat large over the treads, measuring 33.75″. Ultimate wheelsets are almost exactly 33″, the maker must have recognized all the variation by prior makers. Finally, speaking of variation, Nason wheelsets vary a lot; I have found examples that were sized like S-C wheels at 31.5″ and yet others that are almost perfect to scale.

To close, if you are curious about S-C passenger wheelsets, they should be 36″ — but actually measure out at about 37″. Why that is I could not tell you, but these little things do make a difference when setting up cars to operate.