Roland Perry wrote:
In message , at 12:12:28 on
Sat, 24 Jan 2015, e27002 aurora remarked:
given that Crossrail will run thru three different signalling systems,
integrate into the timetables of two franchises, and mix with local
and freight traffic, one can see it will present an operating
challenge.

Three franchises if you count HEx.

True, though the only tracks they'll share are in Heathrow itself, as
Crossrail will use the GW relief lines and HEx is on the mains.