On Fri, 02 May 2008 23:15:13 +0100, Timothy Baldwin wrote:

The standalone Oyster validators at Bank are indeed somewhat
mysterious, though here on utl we have come up with a number of
theories about it in the past, the details of which I forget now!

A passenger touches in in Zones 1 & 2 with Zones 1 & 2 travelcard, then
touches at Beckton. Did they change onto the DLR from LU, or did they leave
at an ungated LU station then travel to Beckton by some other means?

If less than 2 hours pass between touch-in and touching at Beckton,
the system assumes the former. If more than 2 hours, the system
assumes the latter.

(This is irrespective of whether the passenger touched at Bank.)