Conceived from a model seen at Kew Bridge Steam Museum's Magic of Meccano Show some years ago by Mike Fallows, modified to suit. It features two rotating wheels at the end of a medium sized rotating arm. These two outer wheels are driven by chains from the central arm by a 2:1 ratio, important so they appear to rotate.
The model is driven by a Como Drills model-car type motor and could be adapted to a Meccano E15R readily.
For this scale of model some details have been omitted, like cycling the small wheels to load passengers, and a programmer to run the model in a sequential mode.