You have Big Boy running on right tracks and correct location. Most of Big Boy work was mountain climbing over the Rockies during the war years. The art work is great, looks like real thing. If you had much smoke from the stack, then you are not running the locomotive right. I remember old steam engines running through my home town but by time I left high school there was no more steam on the rails. There was 0-2-0 switcher was working up till mid-60's. The switcher belong to meat packing company for moving cars in and out to load product into ice cars. Now meat packer is gone now.[link]
Well yes and no. On a good stretch of straight and level track a fireman can get pretty clean exhaust at the stack however a big locomotive working hard uphill will generate quite a bit of smoke as the fireman pours it on. Witness these Norfolk & Western Y-6 locomotives bringing a heavy coal drag over a mountain: [link]
In any case, buyers want the big, dramatic billowing smokestack. I will most always include some smoke from the stacks of my steam locomotive depictions.
If you have they would not be using it with my consent. I was in negotiations with them last spring for them to carry my art but they wanted too much of a discount on my price. I wouldn't have made any profit. Also, my policy is for payment before I ship and they wanted me to give them credit terms. In the end I decided not to do business with them as it was too one-sided in their favor. I'd be interested if you did see it in one of their catalogues if you could scan the page and post it in your scraps for a day or two so I could copy it.