For my drawing efforts thus far, I’ve been considering the erecting card and the associated specification for the locomotive as gospel. I mean, these were the resources that the boys at Baldwin would have used to put 622 and 621 together, and so they should be right.
Unfortunately, unexpectedly, inexplicably, they don’t agree!
The drawing appears to show a 34 inch truck wheel, while the specification says they should be 30 inches. Now, I know, scaling from a drawing is dangerous business, but with the 3D model coming out quite different from the erecting card, I was filled with self-doubt.
After about an hour of fiddling with the model to try to understand why the frame extensions were waving in the air so far above the engine truck, I finally measured the wheels on the erecting card. They were indeed four inches bigger than specified!
The silver lining was that this prompted me to finally search out all my photos of the engine itself, for those are the final arbiter. I organized the ones that were already digital to the locomotive’s page on my research site; the others, I’ll scan tomorrow and add to the page. I haven’t scaled them yet, and there is no nice side view of the whole engine to make it easy, but it looks to me like the larger wheels are going to win.
It’s tremendously important to have all your photos and other resources on hand when you’re building a model. I’ll be printing the page and posting it above the workbench when it comes time to start modelling for real.