I been looking at the big metal lathe too hard and missed the lathe dead center in the photo. Or is it a lathe? Wood lathe maybe? I bet the photo was made in the early morning, with plenty of light shining in the east windows to the right, before his workers got there, and he shed his suit jacket to get down to work. By 1916, the line shaft was probably ran by a flywheel type gas engine, outside the building. A steam engine required a fireman to watch it, as was done in much larger facilities/factories. I also tell you for all the romance of flat belts and line shafts, they are NOISY to be around, belts slapping, and the open pulleys whirring.