Yeah, of course it is (which is what I originally thought) - but that's very early for a twin coaster. It does look side-friction though - so yeah. It's finding other shots of Derby Racer that's the issue, not many about (I've seen three, two on this page - the other just some trees :lol: ).
It's actually really exciting. The side friction coasters hit in the early 1900's with single cars like Leap-The-Dips. Trained coasters seemed to be Scenic Railways with the brake man. I'm sure there are train coasters which use side friction to help keep the coaster on the track like this, but finding details or photos of them are rare. Generally though, as the Scenics stopped being made, they were replaced by the faster, more exciting, upstop wheel coasters in the early 1920's. I've never seen or heard of this kind of hybrid before.