Well they ran on raw DC around 12v. Did you get the resistive controllers with what you had. I think you can still buy slot racing plunger type controls, but not all have the dynamic breaking wire, otherwise known as a way to short out the track when power moves to zero. It might be also interesting to suggest that you may find what you want in some shops for model hobbyists. There were certainly motorising kits for the plastic car kits you could get. Who makes these these days? Used to be airfix.
The main difference between the main makers of the tracks was the pitch of the brushes on the track. Scalextric are narrow, and Airfix were wide, but often they were made of braid so could be angled to run on either system. Unfortunately I no longer have my cars or you would have been welcome to them. There seem to be three scales out there these days,1/32 1/24 and a very small one which seems to be bespoke for novelty things like batmobiles etc.
Myself I agree the mains units were not that good, for example, some motors used so much current they cooked the controllers and slowed all the other cars down when mixed with them on a track. Far better was separate power units per lane. They did not seemingly work well with smooth DC supplies I found, being lazy to start.
Brian