In message .com,
Boltar writes

Given that one crossrail branch heads into woolwich , will the trains
be dual voltage or will they put 25KV overhead on the DC lines there?

No running is planned on the existing line through Woolwich. Crossrail
will run in tunnel under the Royal Arsenal, with a station just north of
the existing Woolwich station. It stays north of the existing railway
until just past Plumstead, and then rises to the surface, running
parallel to the existing line until the terminus at Abbey Wood - which
will become a four-platform station. So the 3rd-rail and overhead
systems stay entirely separate.
--
Paul Terry