On 18 Oct 2006 15:21:33 -0700, Mizter T wrote:

I've thought about this a bit more and my above explanation (with the
Tottenham Hale via Highbury & Islington to Camden Road example)
could've been a bit clearer.

The critical point is that if you're using PAYG for any portion of your
Tube journey you must touch in and out at the place where you move from
PAYG territory to non-PAYG territory.

Are you sure about this? This is a long-standing question on this
group (at least for those who care about such things, of whom I'm
perhaps the only one), and is still mentally filed in my "unanswered"
category. IIRC it was originally raised by someone who wanted to
travel from Ilford to Liverpool Street (both have barriers with
validators) on a Z34 Travelcard on Oyster, and wanted to know if the
extension would be deducted correctly or if they'd have to leave the
train at Stratford and use a platform validator there, but no one
seemed to know the answer.