On Tue, 02 Oct 2012 20:00:51 +0100, Charles Ellson
wrote:

On Tue, 2 Oct 2012 15:07:03 +0100, "Tim Roll-Pickering"
wrote:

Charles Ellson wrote:

In fact is there a clear list anywhere of which pairs of stations
definitely
are and aren't valid through interchanges on a single ticket?

For Oyster :-
http://www.whatdotheyknow.com/reques...on_interchange

There are also "emergency OSIs" mentioned in :-
http://www.oyster-rail.org.uk/out-of...terchange-osi/
(PVAL = passenger validator)

Thanks. I assume the regular ones are also valid for paper tickets?

Not that I have tried it but if you use the single fare finder on the
TfL website, the same fares are quoted for e.g. North Wembley to
Watford (Met) as are quoted for Northwick Park to Watford (Met) and a
12-minute walk from Kenton to Northwick Park is shown as part of such
a journey when fed into the journey planner for a journey during
normal weekday operation. In practice a "paper ticket" is unlikely to
be used for this journey rather than Oyster or a Travelcard but other
examples could be different if e.g. only a single journey was being
made and the "cash" fare was less than Oyster/Travelcard.

For the cranks: TfL will both quote 1.50 UKP for Watford Junction to
Watford (Met) and show it in the journey planner with the walk from
Kenton to Northwick Park although the details will have to be manually
fed in to the planner because moving from the Oyster fares page
changes the Watford (Met) destination to "Highbury Barn/Ldn
Metropolitan".

I suspect some of the permanent OSIs might be found in assorted
historic ticket inspectors' instructions. IIRC Kilburn High
Road/Kilburn Park and Kenton/Northwick Park (and the now West
Hampsteads?) feature in a 1938 LMS book.

I'm surprised that Aldgate & Aldgate East aren't a regular OSI - the number
of times that a Hammersmith & City train is nowhere to be seen would make
that a sensible route.