On Sat, 16 Feb 2008 18:35:10 -0000, Paul Scott wrote:

Thanks Paul. So imagine this scenario. I have £1.00 on my Oyster and I
want to go from Ruislip to Hackney Central on Saturday night.The TFL
fare finder says the fare is £1.00. I touch in at Ruislip and touch
out at Finchley Rd. The fare for that stretch would also be £1.00 so
in effect is there nothing on my card now ?

I'll leave it to someone else to confirm what happens around £0.00!, but I
don't think your theoretical £1.00 card would work that way. At your first
touch in, £4.00 (the max LU cash fare) is deducted, and when you touch out
after your £1.00 journey, £3.00 is added back, leaving £0. In that case I
wonder if you'd get through a further barrier?

If it's a valid out-of-station interchange, then yes the second entry
barrier will let you through on a balance of £0.00.

Don't know what happens if you take your balance negative by travelling
further than your £1.00 journey though, I've never taken the balance that
low on mine...

I *think* the second entry barrier will also let you through even on a
negative balance (I think I've done it once before, but can't quite
remember for sure).

I wonder what happens if you top up your balance during an
out-of-station interchange? Does it break the continuity of the
journey?