The slot is wider on the Carrera track. This causes the cars to side off the rails. Like Dave said the pick up shoes don't work well with the rails. Our friends in England use Micro Scalextic track with similar rails, which make it necessary for all cars to use braids.
This is a really creative idea! Many aspects of the Carrera track would be perfect for drag racing. Wide lane spacing, reliable electrical connections, long straights (13.5”), strong availability and reasonable prices. For these reasons I occasionally come back to your idea.
Was wondering if someone could insert some sort of custom u-channel in the slot to make it HO compatible. Might be doable with a CNC router. Another idea is to line each side of the slot with thin plastic strips.
Running braids is an easy solution to the the flat rails. It’s been working great on Woodcoat’s Micro Scalextric track.
Earlier I mistakenly mentioned that the rail spacing may be too wide for HO. It turns out to be almost identical to the Micro Scalextric track. So no problems there.
Sorry I'm so late on this one. There was a group in CA in the late 90's early 2000's that used this track. It seemed with some good success. They ran mostly inlines (all different classes) with braid pickups. To handle the wider slot they used plastistruct(?) 1/8" tube over their guide pins. I think I still have a tape from one of their races. They had a nice setup with good racing and fast cars.