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[email protected] · December 3rd 03, 05:46 PM posted to uk.transport.london

In article ,
(Boltar) wrote:

"John Rowland" wrote in
message ...
Hi all,

The rumour mill says that the new surface stock should be ready to
replace
the A, C and D stocks in 2013, and that it will also be used on South
London
Metro services. It will have some method of dealing with curved
platforms

I forsee a problem with that. Will it be 4th rail or 3rd? You can't
have a
4th rail train running over 3rd rail lines because the centre shoe will
foul points without a ramp to lift it over

A ramp shouldn't be needed to lift the shoes as the shoes should be higher
than the running rail (this is certainly so on LUL tracks, and I assume
that mainline rails are the same height. The point fouling problem (if
indeed it is a problem) would still apply on LUL lines as the shoes still
have to pass over the running rails at junctions etc. There may be ramps
at some locations to ensure the shoe is lifted IF it is lower than it
should be, but there aren't ramps provided as a matter of course
everywhere that shoes would pass over the running rail.

Roger