Back a few years ago I started to scratch build a GE 85 ton steeple cab based on the two Hudson Bay Mining and Smelting had the 60 or more Utah copper owned. I finished it about a year ago as a non operational locomotive in a HO scale diorama.
Over the past year I have been designing HO cars in 3D and printing them though Shapeways.com.
The Atlas HH600/660 has a slightly larger bolster to bolster dimension than the actual 85 ton steeple cab but is a good platform for it.
After designing the cab and trucks I have started the locomotive with the plans of making two.

If you've ever tried to mount a Kadee coupler on the front of a steam locomotive, or on the rear of an F-unit, or in any of a number of other tight spots, you know it's sometimes impossible to fit the coupler and box in there and keep something close to a prototypical coupling distance.  Usually, that means the coupler sticks out too far, or you have to resort to drastic measures like cutting off the rear of the coupler shank and drilling a new hole in the remaining shank stub.

But maybe there's a better way?

I just can't resist a box of junk steam engines in need of TLC!  At a train show last weekend, I bought such a box, and inside was (among many other things) an old Mantua 0-4-0, more or less complete.  It runs when I power the brushes directly (didn't even try putting it on the track yet), but it definitely needs some work in both the maintenance and detail departments.