[Scuderia_Turini]

I got this STABO Tankstelle (Filling Station) recently. The Ebay listing didn't describe the functionality, just the appearance and sold for spares/repairs untested. I was intrigued by it and wondered if in fact it was a lap counter. 
The unit came with instructions and it is similar to the vintage Scalextric Fuel Load Gauge. Each pump contains a clockwork mechanism that drives a countdown until the electrical circuit to the relevant lane is cut (so the car stops). 
Unfortunately both units have broken clockwork springs so have not been able to try the unit.
I think the usage is that the winding of the clockwork mechanism for each pump determines how quickly the car will run for so the driver has to judge how much "fuel" is needed to complete the race with the minimum number of stops for a re--fuel (ie re-wind).