On Jan 25, 11:47 am, Andy wrote:
This Saturday there is engineering work which means the the West
Ruislip - Marylebone services are diverted to Paddington. Currently
Oyster PAYG is valid on the Marylebone route, but not into Paddington
(this being on the list for spring 2008). Does anyone know if
provision has made for people touching in at West Ruislip and then not
being able to touch out at Paddington during the diversion? Will the
be posters saying that PAYG is not available or will people have to
phone up about unresolved journeys.

Last Saturday I took the train from West Hampstead thameslink to St
Pancras. Usually PAYG is valid on this route, but because of
engineering work the train ran into the high level platforms at St P,
where there were no gates and no obvious place to touch out, so I got
charged the max cash fare and had to ring the oyster helpline to get
it refunded. I don't know what else I could/should have done.