12 yr old boy ends up in sidings
On Thu, 11 Oct 2012 10:12:51 +0100
Steve Fitzgerald ] wrote:
That's an advantage, but the main reason quoted is to do with keeping
the power supplies separated from earth to stop corrosion of cast iron
tunnel segments. The +420 -210 arrangement facilitates monitoring of
the power supplies.
Probably makes the signalling a bit simpler too if there's no return through
the running rails. Any idea how the waterloo & city coped with tunnel
corrosion when it was 3rd rail as I presume its iron segments there too?
B2003
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