On 17 Feb 2007 05:17:23 -0800, martin j wrote:

Wonder if anyone here can shed some light on this.
My colleague was checking both TFL's travel planner and National
Rail's website for transfer times for a Saturday AM between the above-
mentioned stations. TFL were pretty optimistic, quoting just over 20
mins, using Jubilee to Baker Street, then Bakerloo.
National Rail seemed to have very little faith in London Underground's
services and quoted 1 hour. No detail could be found for which route
their webiste might have determined.
We decided after some discussion, that a midpoint between the 2 times
was probably the most realistic. I'm just surprised there was such a
disparity.
Any comments/suggestions?

The TfL planner gives typical "average" journey times, rather than the
maximum amount of time you should allow for the journey. In fact it
tends to be a bit optimistic - it assumes Tube trains arrive and
depart at exactly the times in the (internal) timetable, and the start
time for the journey is the time you need to be on the correct
platform at London Bridge to catch the scheduled train. It also
doesn't always allow sensible transfer times at interchange stations
(maybe they've improved this recently; I haven't used it in a while).

If I were making the journey myself, even knowing exactly where to go
and without luggage or other people in tow, I wouldn't expect to reach
Baker Street (let alone Paddington) within 20 minutes of stepping off
the train at London Bridge. The minimum I'd want between scheduled
arrival and departure times would be around 40 minutes. If I was going
somewhere like Penzance (i.e. can't just get another train half an
hour later) then it would have to be even higher.

The National Rail planner, I assume, uses the fixed transfer times
shown on p.43 of the NR Timetable[1]. For London Bridge to Paddington,
this is 62 minutes.

If you have an advance-purchase ticket that's only valid on one
particular train from Paddington, you may have to have allowed the
full 62 minutes for the transfer in order to have the ticket accepted
on a later train, in the event of a delay (either on the train to
London Bridge or on the Underground). If you have an open ticket then
this needn't concern you, although you should probably be allowing
around that amount of time anyway.

[1]
See p.43 of:
http://www.networkrail.co.uk/browse%...nformation.pdf