Best of luck with your project. This is part of a steam tractor I started 24 years ago ...and stopped working on about 21 years ago. I've spent the last couple of months re-making bits of the engine I wasn't happy with and then finishing the engine to the point of getting it to run.
Yes, a gear is keyed to the far end of the crankshaft which then drives the 2nd shaft which runs in those bearings. That has a sliding gear cluster on the end by the flywheel which drives a stub 3rd shaft, then from there it's chain drive to the rear axle. The engine forms a self-contained unit, so can be built and run independantly from everything else.
Not sure of the details, needed to visit someone else to get access to an air compressor. There were a couple of fergies and other stuff lurking in the shadows and corners.
