asdf wrote:
On Tue, 26 Sep 2006 17:52:52 GMT, Richard J. wrote:

Actually the PAYG fare would be for Zones 3-6, otherwise he would
not have a valid ticket between Northfields and Boston Manor
(across the zone 3/4 boundary). The costs are the same, though.

Actually it would be for 4-6, because his travelcard covers zones
1-3, and so the extension would be for the additional zones he is
travelling through - zones 4-6. Otherwise he'd be paying twice
for zone 3.

The travelcard covers his journey as far as Northfields (zone 3)
and not beyond. He then needs an extension which is valid from
Northfields to Heathrow, which has to be a zone 3-6 single. Your
logic would work if Northfields were a boundary station in both
zones 3 and 4, but it isn't.

As others have said, this is not how it works in practice. If you
like, the Travelcard is valid to the Z3/4 boundary (a point on the
track somewhere between Northfields and Boston Manor), and only a
Z4-6 single is needed to cover from there to Heathrow.

Yes, of course! Now you explain it like that, it seems obvious. Please
ignore my previous posts in this thread. I should have known better than
to try to correct Barry Salter on ticketing!
--
Richard J.
(to e-mail me, swap uk and yon in address)