There are some "Critters" made from Athearn HO Scale motors/frames and Shapeways castings that are fun and loaded by the builders with detail. They overhang the track and roadbed realistically..
With Bachmann steamers; I tend to remove most of the detail and re-detail them with 1:48 scale wiseman parts, again improving the believability. This is an easy way to get a much more realistic steamer