Hi Il Grifone and thanks for the welcome.
Pickup is from 2 interleaved bronze strips with a black plastic strip between them, with pickups on the front and the rear wheels - not the central unflanged driven wheel. It sounds from what you say as if the motor ( and pinion ? ) may not be correct as there seems to be no fixing screws, or holes, for the motor which is housed in a black plastic framework. The plastic gear wheel seems worn on one side as if the pinion has been wearing it away rather than engaging. Beginning to think this 94xx may end up populating the engine shed! Any pictures would more than welcome.