My brother used to collect Scalextric cars and had about 400 until he sold them to pay for central heating. I’d have just put a jumper on.
This was before the days of ebay, so I think he just got them through adverts in the local papers.
He’d usually buy a complete set because it contained a car he wanted, then end up with loads of surplus track.
Slowoldman, I did that as well. Clear acetate bodies, painted on the inside, mounted on scratch built chassis.
I used to wind my own motors as well, filling the armatures with melted araldite over my mums gas cooker, then balancing them on two razor blades. 🙂