Eurostar, a high-speed train service linking the U.K., France and Belgium, will partner with the social payments provider iZettle to process passenger upgrades. Eurostar will use iZettle's chip-and-PIN mobile point-of-sale readers on its fleet of trains to service passengers who decide to upgrade their travel class after the trip begins.

Eurostar said it processed more than £300,000 worth of upgrades in 2012 through on-board transactions; the company said iZettle's platform will help process upgrades more quickly and allow it to serve more customers. That's said to be particularly important in December, when tens of thousands of travelers cross between the three countries over the festive period.

In conjunction with iZettle's free app, the card reader connects wirelessly via Bluetooth to a smartphone or tablet to allow users to accept card payments. The reader works with all major credit cards, iZettle said, including Visa, MasterCard and American Express.

"We believe that our passengers' journeys should be seamless, from the start of the booking process right through to arrival at their destination," James Blackwood, Eurostar on-board services general manager, said in a news release.

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