On Sun, 21 Jun 2015 02:04:13 +0000 (UTC), Recliner
wrote:

Basil Jet wrote:
On 2015\06\21 02:45, Recliner wrote:
Basil Jet wrote:

IIRC Drayton Park has both fourth rail and overhead,
although obviously not for much distance.

The fourth rail isn't operational. It was disconnected when the overhead
was installed. It does have a short length of third rail and overhead, but
that's not uncommon.

This seems to imply that overhead + 4th rail is in some way harder to do
than overhead + 3rd rail... I would have thought it would be the other way around.

c.313s don't use the fourth rail so it is redundant.

I think it just so happens that no fourth rail DC trains normally share
tracks with any overhead line AC trains.

Not since the DC line was converted to 3rd rail.