On Sat, 17 Mar 2007 10:41:40 +0000, Dave A wrote:

Both of those comments scream out common sense. I'm sure that I read
somewhere (a couple of years ago) that there were plans to move the AC/DC
changeover point further south (it may even have been at Shepherds Bush
station) for practical reasons, BICBW.

There have been plans to do this for some time, but the issue is the
Hammersmith & City line - AIUI the signalling is not immunised, so the
overhead can't be extended south until the H&C gets resignalled (which
may not be until 2014).

It *could* be extended south before then, but that would mean having
to pay for the existing H&C signalling to be immunised (as well as
that on the Central). They've decided it's too expensive, but said
they might reconsider when the H&C signalling is renewed (and it'll be
cheaper to have it immunised).