On Mon, 22 Feb 2010 10:42:17 +0000, David Hansen
wrote:

The logic is that on a bus or tram one touches the yellow pad on
entering a bus or tram, on a train one touches the yellow pad on
entering and leaving the railway. Too complicated already, but at
least understandable.

Then something else is added for using some trains. Illogical.

Trains for which you don't have a valid ticket, unless you buy one.
Which by this delivery system means adding it electronically to your
card. Or. as people with season tickets would do elsewhere in the UK,
going to a station[1] and buying a paper ticket for the part of the
journey not covered.

[1] or online, or on train, etc etc.