The FAQ below has an aura of Solo/Electron about it.

Does anyone here have experience of using the Orange Prepay Card (with
contactless technology) on TfL?

http://cash.orange.co.uk/faq/#q3

What does "for electronic use only" mean?

You’ll notice that your card has "for electronic use only" written on
the top right hand corner. This doesn’t affect using the card online,
over the phone or at an ATM.It simply means that you can only use it
wherever Magnetic Stripe cards are accepted and in the normal Chip &
PIN terminals in the UK and around the world.

The card can’t be used in the older manual sliding type of card
machines, as it doesn’t feature raised numbers. Similarly, you might
not be able to use your card on a plane or train as there may not be
an electronic connection available.
--
Roland Perry