[personal profile] nojay 2018-01-28 12:46 pm (UTC)(link)
The idea, as I understand it is that a validating terminal on the tram would allow people to avoid paying for a trip on a smartcard unless they see the ticket inspector coming along the carriage at which point they can make a mad rush for the validating terminal.

It doesn't apply on the Edinburgh trams for various reasons -- most passes are "all you can eat" unlimited travel cards rather than working as pre-paid debit cards like Oyster, Suica etc. so not validating the card doesn't save anyone any money. There would be no ticket-issuing machines on board.

From speaking to a conductor they validate passes so that the trams revenue stream can be separated from Lothian buses since the smartcards interoperate on the two services. The cards are checked 100% on entry to the bus but there are too many doors on a tram to enforce that check on boarding hence the patrolling conductor who checks tickets and smartcards most of the time (but not always).

The contactless debit card payment scheme (and smartphone-pay too) is a no-brainer solution for people digging through their wallets and bags to find enough change to buy tickets while the tram is pulling into the platform. It should have been implemented a lot earlier but wasn't for some reason.