About 60,000 Oyster smart cards were made inoperable over the weekend when the cards were swiped at ticket gates in the London Underground. Transportation for London is working with card supplier Transys to figure out exactly how this happened.

As it stands now, there is no word on what caused the damage to the huge number of smartcards. ZDNet UK says the first cards were affected on Saturday at 5:30am BST and that the problem was fixed by 9:30am.

"We're currently investigating the cause of the incident with Transys," a TfL spokesperson told ZDNet.co.uk. "It's an ongoing investigation."

Via ZDNet UK