TheOneKEA wrote:
Kentish Town - Elephant & Castle / London Bridge

Thameslink in the central zone I presume... Am I right that PrePay is
available at City Thameslink?

I have seen standalone validators at City Thameslink. I suspect PrePay
is valid there.

Yes, and at all other TL stations between KT - E&C/LB

Marylebone - Amersham

Duplicating the Met plus allowing the London terminal rather than have
everyone changing trains at Harrow on the Hill to arrive at a very nearby
station.

This route isn't really a duplication IMO, it's an enhancement.
Chiltern probably decided to implement through PrePay ticketing because
they knew that from the POV of Met passengers, their Aylesbury line
services are the same as the Met services. Besides the long tradition
of through ticketing makes it less of a duplication than the other
routes.

The latter is the important factor: Chiltern (and all the other
operators on inter-available routes) are obliged to accept LU tickets
on this route, whether they're formatted as paper or Oyster prepay,
under agreements with BR (and quite possibly its predecessors) that are
written into the current TOCs' franchise agreements.

Marylebone - West Ruislip (only intermediately at South Ruislip)

Similarly with the Central Line I guess, although the Marylebone to South
Ruislip section isn't really duplicating the Central in a meaningful sense
or going to cause bizarre interchange habits is it?

This isn't really a duplication either. I think Chiltern first accepted
it because it doesn't make sense to only allow NR trips between the
Ruislips on PrePay. Now that Wembley Stadium station is increasing in
importance, Chiltern might start accepting PrePay there too (in fact,
they should definitely do so IMO).

They certainly should. Whether they -will- is another question,
especially as their franchise isn't up for renegotiation any time soon.
I suspect any changes would have to involve Ken throwing them some
money...

--
John Band
john at johnband dot org
www.johnband.org