"Peter Corser" wrote in message
...
Manual switching is not fast enough - regen was always a problem on LUL
due to conductor rail gaps and no through train power bus being allowed.

It has become viable with solid state switching which is fast enough to
detect the gap and virtually instantaneously divert the current to braking
resistors, etc on the train (temporary loss of braking would be
undesirable, at the least!).

Taking this a stage further it would be relatively straightforward to
detect whether the negative rail is at LUL type potential (i.e truly a
negative rail) or at earth potential as on NR tracks. I don't know if
this is the way it is going to be done, but is certainly feasible.

Peter

PS I presume that regen will not be allowed on NR sections due to the
potentially enhanced performance of "conventional" NR stock in the section
when regen is taking place.
--
Peter & Elizabeth Corser
Leighton Buzzard, UK

The track power supplies have to be able to accept regeneration without
identifying it as a fault, i.e. transfer the incoming power to elsewhere in
the system with a demand. The system nominal voltage shouldn't rise
significantly. A lot of NR stock is capable of regeneration, but it is the
infrastructure that limits its use. I doubt this applies to the old wrecks
that meet LU at Richmond/Gunnersbury though...

Paul