Can anyone come up with a SIMPLE push rod or beam drive for a sternwheel which works without engineering skills or jewellers accuracy? I want something which looks about right and works simply.  Regards, Walter.

Are you using electric motors?

I'd probably make something like this, but it depends how realistic it has to look. A propeller shaft with crown wheel and pinion arrangement, in line with and behind the frame on one side provides drive (the other side would have some kind of fake valve eccentric that matches the crown wheel in colour) Pitman arms slide freely in 'boxes' set into the rear of the engine room area...