Belg,
As far as I know, there were three main types of engines used for logging, the Shay, Climax, and Heisler locos. Bachmann makes a Shay in their Spectrum line, I've heard great things about it. MDC makes Shays too, as well as a Climax, and Rivarossi makes Heislers. I've heard that the MDC engines need a little tweaking to make them run really well, and I don't think I've heard anything either way about the Riv's.
Bear in mind that logging operations were often shoe-string outfits, they often cobbled together their own equipment and would run whatever they could get cheap and would do the job. That's why a lot of folks love those lines, they could do things they'd never be able to justify on a mainline railroad.