Hi Jack.
As a new reader to this thread and trying to build a smallish terminal branch I think the idea of joining modules together very interesting. To comply, I would have to keep my access rail straight, and put a length of board at the buffer end to make it a through station.
There is just a couple of things that I think need to be worked out.
1. Would it not be better to have the modules free standing and the same height, but having screws on the legs for small adjustments? This would relieve the problem for the depth for the point motors, and of course of any differences with manufacture.
2. The bridge. The idea that has been given (photo’s) is spot on if everyone made them out of the same size timber, but, it would need a small amount of protrusion leading on to each module, about one inch. This would give an amount of rigidity to the bridge and help support the rail, I know there would be the problem of wear and tear, but as the modules would only be joined together occasionally, I don’t think it would be much of a problem.
I hope I haven’t caused a problem with this idea but after reading all the comments there seems to be a bit of confusion as to the working heights etc.
Alan