On Mon, 13 Nov 2006, TheOneKEA wrote:

While doing a bit of idle research into the upcoming Standard Stock (aka
'S' Stock) being designed for the Underground's Sub Surface Lines, I
came across an interesting note which stated that regenerative braking
is to be provided and used by the S stock on the SSL lines,

At last!

and _only_ on the SSL lines - the S stock running District Line services
to Richmond and Wimbledon will not regenerate when they are on NR
metals.

ISTR a Doctor Who season finale along much the same lines.

Sorry.

I'm guessing that the trains will achieve this by using some kind of
mechanism which can detect the voltage level of the negative pole of the
traction circuit and subsequently cut in the regen mechanism when the
negative pole is within the appropriate voltage range. Does anyone know
how this could be accomplished?

Using the running rails as a voltage reference would be the obvious way to
do it. AIUI, there is a voltage across them from track circuits, but it's
small enough that it shouldn't matter.

However, i wouldn't be at all surprised if the way it actually worked was
that the driver had to flip a switch to turn the regenerator off!

tom

--
Osteoclasts = monsters from the DEEP -- Andrew