Mizter T wrote:

In terms of NR adopting Oyster PAYG I guess how this will work is that
for any A to B journey a fare will be set according to the most likely
route taken - i.e. which zones will a passenger on this journey pass
through. Then if the passenger goes a more roundabout route, avoiding
zone 1 for example, if they touch-in their Oyster at the interchange
points they'll be charged for the cheaper journey.

And yet the Underground has been slow to adopt this, for examples such as
Harrow on the Hill to Hammersmith (particularly relevant this weekend
because of engineering works on the route involving changing at Baker
Street) as well as possibly the North London Line - will travelcard on
Oyster holders get charged extensions for a "most likely route" involving
zones they don't have, even if they've travelled within their own zones.

(Also how is a "single fare for any route" compatible with a strategy aimed
at encouraging people to bypass zone 1 on orbital routes, using cheaper
fares as an incentive for potentially longer journeys?)

It's too late for me to start working out elaborate examples. However I
think in many cases a passenger would encounter a set of gates on their
journey - say when changing from NR to the Undergound at termini - that
means this isn't actually as much of an issue as some think.

I'm not so sure - a good number of interchanges have NR and Underground all
together behind the gatelines - e.g. Barking, Stratford, Moorgate,
Farringdon, Highbury & Islington, Willesden Junction, Ealing Broadway,
Wimbledon, Richmond, New Cross & Gate... to name but several. And some of
these (particular Stratford, bar the Jubilee Line) are so mixed together
that there's no real way to put barriers in.

Off the top of my head I can think of one situation where it would seem
that Oyster PAYG couldn't cope with working out what route passengers
had taken. Peckham Rye is in zone 2 and has a half-hourly service via
Lewisham to Dartford. It also has very regular services to London
Bridge. Let's say a passenger is travelling to Lewisham - as the
passenger can change at London Bridge onto a Lewisham-bound train
without encountering barriers the system won't have any record of
whether their route was via London Bridge - and hence zone 1 - or not.

Another obvious one are the three Lewisham to Dartford lines - how does the
system know if someone's travelled via Lewisham (zone 2/3), Dartford
(outside the zones) or the track between Crayford and Barnehurst or Slade
Green (all within zone 6) shown on the map but possibly not having a very
good service (I have no idea) providing all four combinations?

Perhaps the solution for this is to require passengers using PAYG to
touch-in at every interchange station. For many journeys this might not
be strictly necessary for the system to determine the route taken, but
for others it would be necessary. This could be explained to passengers
thus "Please touch-in at every interchange to ensure you recieve the
best fare". If they didn't touch-in at the interchanges then by default
there'd be charged the more expensive fare.

Is this practical though? Some interchanges get very busy and readers are
not easily located. Try doing this on the eastbound Central/Ilford-bound
platform at Stratford in the rush hour when you're also trying to work out
just which stations the train about to pull out calls at!

There are I'm sure people working on this now at TfL - I just hope that
they have a good idea of what they're doing and are going to be
consistant in it's implementation, and they don't bog it up.

So how do they handle it at present?