This next version creates two separate routes: an outside-loop at O60; and a loop-to-spiral_loop-to-loop route. It gives up the original idea of a single-track with three sidings, for these two routes.
For continuous running, a train can run on the O60 (O54), and two trains on the O48 passing in the spriral-loop siding (automated stop and wait). And a fourth train on the On30.
