Barry Salter wrote:
On 11/11/2012 12:57, Recliner wrote:

Thanks, yes it's confusing how bits of the Chiltern lines that parallel or
share LU lines have 24 availability, but others don't.

The only bit that may seem less than obvious at first is South Ruislip -
West Ruislip. It's perfectly logical though, as the gates at each end
won't know whether you've travelled on Chiltern or the Central Line.

And Marylebone - Amersham is an extension of the interavailability of paper tickets.

Unfortunately for me, my nearest station is one of the Chiltern ones that
doesn't participate in this (even though it has Oyster OSI with a nearby
Tube station).