"Mizter T" wrote

What would the benefits of ditching HEx be for Crossrail, apart from
increased passenger numbers - would it just be more capacity in the
Heathrow tunnels?

I'd be surprised if HEx was ditched, as it will still be quite a bit quicker
from Paddington than Crossrail, but Crossrail will mean a rethink. I expect
that TfL will want to bring Heathrow via Crossrail into the Travelcard
zones, which will call into question the premium fares on HEx. I also expect
that TfL would want Crossrail to go to T5, which causes problems for serving
T4 - should HEx revert to T4, leaving its passengers to change for the much
busier T5? Or should the HEx link to T4 be abandoned? And will two platforms
at T5 suffice for HEx and Crossrail?

Peter