Discussion about this post

User's avatar
Bungdit Din's avatar

When London Underground debuted its new ticket machines in the mid 80s, it didn't take long for teenagers to work out that wrapping a 2p coin with foil in such a way as to approximate the contours of a 50p piece would be accepted by the machine as a genuine 50p.

The flourish, however, was to buy an expensive weekly or monthly, load the machine with the dodgy coins, and promptly press cancel. The coin drums were giant carousels, and for every foil coin loaded at the top, a real one would be returned below. In this way it was easy to make upwards of thirty pounds at 1988 money, to sit in one's pocket alongside altered phonecards and voicemail retrievers.

Wonderful article dear boy, insightful and genuinely entertaining with it.

Expand full comment
Miles Thomas's avatar

Without saying too much (and I do have professional experience in this area, and also retail POS), TfL chosen method of operations has traded reliability for valid card holders over declining invalid cards; and also simplicity of implementation, and minimisation of acquiring bank fees. The card schemes and acquiring bank capabilities were not designed to support this sort of transit ticketing at volume.

Could TfL achieve a better rate of accurate declines while maintaining reliable valid acceptances? Yes, with some additional development to detect intra-day cards that can't "settle" outstanding charges and add to block list. Without causing foreign tourists to be charged additional fees. This is not easy development to deliver at scale.

The acceptance of "restaurant" cards is however careless in my opinion; such cards are likely identifiable by the prefix of the card number (called the BIN, identifying issuing bank); the administrative challenge is keeping up with a changing list of cards issued for limited use purposes. TfL's acquiring banks should be assisting TfL's in house team (or Cubic) with that task.

I suspect the contactless card ticketing machines used on buses outside of London may have similar loopholes for similar reasons.

Expand full comment
7 more comments...

No posts