On Sat, 9 May 2009 21:16:22 +0100, Tom Anderson
wrote:

On Sat, 9 May 2009, GazK wrote:

Tom Anderson wrote:

IMHO It is very likely that I Kingdom Brunel would welcome
electrification. He seemed very keen to find a better, cleaner form
of motive power.

He would have insisted on using 3 phase 37.278kV* electrification at
16.25Hz fed through side contact 3rd and 4th rail - and bugger the through
running!

* there is a logic behind this number. See if you can work it out!

Dunno, but getting three-phase power through two conductors is an
interesting idea.

... running rail(s) for the third phase. I'm not making this up, it has been
done before, in Italy and elsewhe

http://en.wikipedia.org/wiki/Railway...urrent_systems

That seems a little bit ... yikes.

Thinking about it, though, it's no worse than using the running rails for
current return in a one-phase system, is it? I'm not sure why i thought it
would be.

I don't know about the Italian system but the American one had single
speed locomotives because the AC motors were synchronous.

Which didn't really matter for the slow speed freight trains in the
Cascades.

tom