Scalextric a253

[gem_mother]

Whilst looking through my Dad's old track from the 1960s, I cam across a piece of track which has the reference number A/253. It has strange groves on part of the metal track and has axtra wires underneath it. The wires connect into a small box with holes in it that says "plug in here". I have searched the internet for it, and cannot find out what it is and what it does. If anybody could help, that would be great.

[Dagman]

Maybe it's a lap counter. I assume it isn't the power for the cars?