In message c.uk, Alan
J. Flavell writes

What about passengers landing at Heathrow - will they be able to buy a
travelcard there? Presumably if the Piccy line isn't operating, then
the LUL station wouldn't need to open - if so, where would the punters
get their travelcard?

The Piccadilly is still operating between Heathrow and Acton Town - so
the LU ticket office will be open. In any case, I think the Heathrow
Express machines and office sell travelcards, as many people want them
for onward travel once they get to Paddington.

--
Paul Terry