John B wrote:
On 1 Jul, 22:01, (Colin Rosenstiel) wrote:
Regen braking has a
place here, too, if you can shove the heat from the necessary
resistors outside.
If it's regen braking, rather than rheostatic, the heat goes as energy to
other trains and not into resistors.

Ish. On AC, absolutely right; on DC, you need banks of resistors as
well because putting it back to the grid if there isn't a conveniently
placed train to take it is Too Bloody Hard. However, given the traffic
density on LUL, most of the time there'll be someone accelerating
while you're breaking so it should work out OK...


Yes, that's what I was getting at. In mitigation, I hadn't read Cap'n
Deltic's latest screed in MR at that point, which suggests that
receptivity in DC networks is higher than previously thought, so you
might not need as much resistance capacity and associated cooling around
the place.

What's the effect of the suggested upping of the voltage to 750v DC on
some lines? Being a concrete'n'steel type engineer (manqué) I don't
understand electricity as well as I should.

Tom