In message , Bill Wright
writes
On 10/05/2018 10:04, Graeme wrote:

It is a problem those of us involved with old toy trains are well
aware of, using up to, say, 20v/5amp, but more usually 12-15v/1amp.*
Even with longer track lengths (36 inches) and good, tight rail
connections, the difference across an oval can be substantial,

An oval? I thought it was two semicircles connected by two straights?
For an oval you'd need an infinite range of differently curved tracks,
wouldn't you?

YKWIM :-)

--
Graeme