On Thursday, 3 April 2014 20:24:56 UTC+1, Richard wrote:
I wonder what the figures are? What would the PAYG single fare need

to be for a change to transfers to need no extra subsidy? Yes,

occasional return journeys might be made, in the same way that a

second journey might be possible with a rail OSI. You could make a

transfer only to a different route, but that would remove the benefit

of not faffing about with transfer tickets during disruption (or a

planned event).

Occasional return journeys for a single fare happen already on Tramlink. Actually probably not that occasional, it's happened to me a fair few times when I've, say, hopped into Croydon to visit my bank (which is next to a stop) and straight back. I can't remember, and can't find, what the maximum journey time allowed on one touch-in is but I think it's fairly generous.

Thinking about this, I've also had similar on a bus. I caught a bus to its terminus, went to a shop and was back at the terminus in time to catch the same bus back. The ticket machine refused my card with something like "passback attempted". The driver remembered me from earlier and just waved me on..

The OSI time between London Bridge Underground and NR is 40 minutes, far greater than I need if I know my train time[1] so I've often used it to leave the station to do something quickly.

[1] The downside of OSI times at Underground/NR interchanges is that if something goes wrong on the NR side it's easy to exceed them and be charged for two journeys. A problem that generally won't happen in the the reverse (NR to Underground) direction as unlike on NR you go through the gateline without waiting for your train to be there / announced.