Anybody ever tried this? I haven’t, but the technique is in use here, and it might be worth considering in some situations.
Perth is the fastest-growing city in Oz, mainly because of the resources boom that’s centred on Western Australia, a state almost as big as the US east of the Missisippi. One of the side-effects of this population growth has been a big expansion of the commuter RR network, including a new line to the city’s northern suburbs.
My friend Peter was engineer in charge of getting the track for the new line out of Perth city and into the freeway centre island that carries the main line north. This involved creating a sharp “S” bend under several freeway overpasses, presenting a curve radius problem not unlike those faced by many model railroad aficionados.
A dedicated commuter RR doesn’t need the same heavyweight rail required by goods traffic, so the initial plan was to use lightweight rail similar to that in place on other metropolitan passenger lines. However, for several reasons the plan was altered to upgrade the rail to a more “standard” thickness. This allowed Peter to grind the track in the “S” bend, bevelling it so the train tilts slightly as it negotiates the curve. It’s analogous to the way you’d lean a motorbike into a bend in the road.
Peter invited me down to have a look just after the first stage of the line was finished. There is not a lot of visible evidence of grinding on the rail, though it’s there if you look closely. When travelling on the train, there’s a lot of screeching as the carriages go through the “S” bend, and a very noticeable increase in speed as the train pulls out of it.
It was good fun standing on the narrow concrete walkway in the middle of the “S” bend, a train crawling by only a metre or so away. Peter reckoned trains occasionally pass that point going in both directions - that would be something to see and hear!
We walked down to the point where the heavy rail for the northern line meets the lighter rail used on most other Perth metro lines. Standing right next to it, the graduated weld was obvious, but as a passenger you’d never know it was there.
For toy trains, it’s probably easier just to tilt the roadbed. However, if you’re ever in a position where this isn’t an easy option (e.g., on a concrete path), grinding might just get your train around that impossible corner.