"Walter Briscoe" wrote in message
...

(And I'm pretty sure that Marylebone NR and Baker Street LU are tied
together as being a valid OOSI, and I think this is also the case
with
regards to Fenchurch Street NR and Tower Hill LU - though annoyingly
Paddington NR and Lancaster Gate LU is not an OOSI.)

Both true. As is Euston Square and Euston but not ES and Warren
Street.
I've just been through to LU customer services and got one of the
more helpful members of their staff. They will try to assemble a list
of those interchanges. If they do, I will forward here.

They've just followed up to ask me to couch my request for information
as a Freedom of Information Act request. Heigh Ho!

They answered me, yesterday. Unfortunately, I can't copy the data un
the answer as they put the following in the reply: "Brief extracts of
the material may be reproduced under the fair dealing provisions of
the Copyright, Designs and Patents Act 1998". I think they mistakenly
refer to the 1988 Act, but know nothing and may be wrong.

It seems you weren't the only one who asked.

http://londonreconnections.blogspot....ent.html#links

Times for interchange are not always symmetrical. e.g.
40 is allowed from Aldgate to London Fenchurch Street.

That is because of the frequency of trains from Fenchurch Street. If you
just miss a 2tph service then you may have to wait 20-25 minutes before
the platform of the next train is announced and you can pass through the
ticket barriers. So the interchange time has to allow for the worst case
scenario.

Peter Smyth