On 10/05/2018 16:57, Graeme wrote:
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
awareÂ* of, using up to, say, 20v/5amp, but more usually 12-15v/1amp.
Even withÂ* longer track lengths (36 inches) and good, tight rail
connections, theÂ* 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 :-)

I had a ferocious geometry teacher. He would point to an ellipse on the
blackboard and ask the class what it was. Anyone who said it was an oval
regretted it.

Bill