I finally got round to wiring up the layout ! It was a massive job. An on off switch on the front face and a USB cable to provide the motors 5v supply. Job done.

The original plan was to have the rotating track set on an incline, with the lowest point at the front, the logic being the train would always find the low point and remaib stationary at the front as the track moved. That plan failed, I didn't factor in friction and could never get the train to remain convincingly stable. So having found a paint brush at the back buffer beam worked, I enhanced that idea to a paperclip. Which works perfectly. Once I have built a couple of wagons, the paperclip can move further back and more out of sight.