"Hugo Rogers" wrote in message
...
On 13/04/2010 08:06, Mortimer wrote:
"Charles Ellson" wrote in message
...
the DC line is 650v which ISTR has been stencilled on many trackside
cabinets for years. OTOH the native trains have been able to run on
750v since at least the c.501 if not also the immediately preceding
LMS trains. ATM there doesn't seem to be an "official" confirmation
which leaps to the front of the Google queue.

I noticed as I was travelling on the GW main line between Didcot and
Paddington that there are lineside cabinets labelled "650V" miles away
from the sections where the London Transport lines run alongside - or
even where the line is OHLE electrified. From memory I think I saw them
around the Maidenhead-Twyford area. What are they for?

they will either be for signalling equipment or for the GSM R transmitters
or they could be for the proposed GW line electrification.

Would signalling or GSM use such high voltages? I'd expect low voltages for
anything that didn't require large amounts of power and would therefore
incur I-squared-R losses. I thought that the proposed GW electrification
would be OHLE, so why would it need 650V supplies?