Logging locomotive depot

Depends upon the size of the railroad. Smaller outfits that just had one loco often didn't have any real depot for the loco but left it out in the weather. There usually was at least a small building or shed that held the spare parts and tools. Somewhat larger logging outfits would build a building that they could put the loco into and do any repairs on it. Major stuff like retubing a loco would be often done at another location as this was specialized work that required certified boilermakers and so forth. It wasn't until you got to the larger outfits that you would see full shops that could do anything to a loco and even then, the building was usually just a one or two stall rectangular building to do the work in. The buildings at such a place would be just about twice the length of the loco at the largest (you only need about 20' in front of a loco to get the tubes out without problems. I've not seen a full roundhouse type setup with any logging railroad as these were complex structures that just didn't justify the cost.

-- Why do penguins walk so far to get to their nesting grounds?

Are you talking about an engine "shed"? Logging companies rarely got fancy with these. So, you could build just about anything with a pair of doors on the front, and a couple of water barrels in appropriate locations, and it could be accepted as prototypical. The McCabe Lumber Co. series of kits has a couple of sheds. Take a look at them at