I think it's similar to the early electric cars that could only go so far as the mains plug would allow.

IGMC

Would that not be some sort of scalextric set?

If we hooked into the existing tram network in those cities that have them, we could feasibly connect the tracks up to the mains and have us all travel around in large plastic cars that impossible to control.

Drawings n' that

That'd be awesome! And we'd never need mechanics again, as it'd just be case of getting underneath and flattening/straightening the brushes out again.

And the headlights would randomly stop/start working for no apparent reason.

And random sections of track would lose power despite being connected perfectly and having every appearance of being totally fine.