Thread: The Bletchley Fly-over
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Old April 23rd 16, 04:20 PM posted to uk.transport.london,misc.transport.urban-transit,uk.railway
e27002 aurora e27002 aurora is offline
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Default The Bletchley Fly-over and Verney Junction
On Mon, 18 Apr 2016 09:48:43 -0700 (PDT), wrote:

On Monday, 18 April 2016 17:41:04 UTC+1, bob wrote:
Recliner wrote:
Charles Ellson wrote:
On Sun, 17 Apr 2016 18:29:31 -0500, Christopher A. Lee
wrote:

On Sun, 17 Apr 2016 20:56:35 -0000 (UTC), Recliner
wrote:


What's wrong with just using 3rd rail beyond Amersham,

More expensive, obsolete, less efficient and it's heading toward 25kV
territory.

Much *cheaper*, surely? Less efficient, yes, but why should it matter that
it's headed towards 25kV territory?

The high cost of DC 3rd rail comes from the need for more complex and far
more frequent substations. You can get a lot of 25 kV line covered from a
single feed.

True, but how does that compare to the costs of rebuilding
dozens of bridges and tunnels on a line?

If memory serves, after the construction of the GC London Extension,
Metropolitan Railway trains were out of gauge north of Quainton Road
on the GC. They were too wide. OTOH, GC trains were out of gauge
between Finchley Road and Baker Street, they were too tall. I suspect
running 25kV out of Marylebone would not be especially challenging.
The structurer gauge being quite generous.
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