I believe Brian is correct about the OLC hotel at Bates doubling as a depot for SVRy. I have seen one photo in which a building that appeared to be an engine house/machine shop existed at Bates, presumably for the OLC to maintain their engines is caught at a distance. Interestingly, Earl Emlaw who had a part in manangment of OLC and SVRy in various positions such as Chief Engineer, Valuation agent, purchasing agent refered to the OLC mainline down the middle fork as the "Grant County Railroad". In the late 30's Whitney Engineering/Heisler records show correspondence refering to OLC requesting boiler specs for the 100 and 104 for the ICC and they were in a hurry to get the information. It was basically the info that would today be required for a form 4. Why would this have been required unless OLC found it's middle fork loggging mainline under ICC. Out of ignorance perhaps, I would have thought a logging line exempt?
Going back to Austin, the engine house of course has been already stated was 4 stall, but at some point, and I can probably cite a date with a little research in the AFE's, the 3rd stall was converted to shop space. When they went to oil burning, a boiler was installed at Austin for heating the fuel oil, but I am not sure if it went in the engine house or a seperate building adjacent.