If you’re having to share the room between a bed and a layout, you probably could do an “around the walls” type design.
As for a locomotive, you could buy, say, an older type of switcher, maybe a NW2, SW600, SW9, or even a SW1 if you can find one, decorated for whatever RR suits your style. If you go for modern mining, you can simply paint out the roadname and put your mine’s name on it instead, or maybe XYZ Leasing, or something. I wouldn’t even change the number. This could be entirely realistic and prototypical, happens all the time with larger, older road units (and switchers, too, I’m sure, just haven’t seen any lately).
The SW1’s came out in the late 30’s, and NS even has some on their roster today. The NW2’s and some others listed came out in the 40’s and early 50’s and many are still going today. It is correct to use switchers either alone, or in sets or 2 or more, even mixed with road units on occasion.
If a switcher isn’t your style, an F7 or F3 would be another good choice. Many were sold off to mining companies after their mainline careers had ended, and quite a few still run today. GP7’s and GP9’s also fit this role.
If you prefer steam, as Texas Zepher said, Shays and Climaxes could work for an old time logging or mining line, but most were retired by the 50’s. There are still a few around, but mostly for tourist lines now. For a layout with 18" Curves, I would stick with shorter engines, such as 2-6-0, 2-8-0, 4-6-2, 2-8-2, or 2-10-0 wheel arrangements. IHC makes good steamers, Bachmann Spectrum made the 2-10-0 “Russian Decapod”, which is a good smaller engine. I wouldn’t go any larger than the 2-8-2 unless you install 22" or larger curves.
I’m lost myself on “shipping train”. A bit more info and maybe we can properly identify what you mean?
As far as brands, here’s a brief rundown:
Athearn - Good quality (usually), good prices. Great dollar value. Somewhat noisy.
Athearn Genesis - See Atla