Half of Tyne and Wear Metro passengers no longer use cash to pay for their journeys, it has been revealed.
Nexus, the operator of the system, says there has been a huge switch towards credit and debit cards, as well as contactless payments.
Meanwhile, many passengers also hold Pop smart cards, negating the need to pay with notes and coins.
Ticket machines that accept bank card payments and smartcards, as well as notes and coins, were introduced at all 60 Metro stations in June 2013.
In 2017, there were nine million transactions at Metro ticket machines, with two-thirds of them made using contactless cards.
Nexus says that Pop Pay As You Go now accounts for 7% of Metro journeys.
Nexus customer services director Huw Lewis said: “Cashless and contactless payments on Metro are now overtaking the use of notes and coins, as our passengers choose easier and quicker ways to pay for their travel.
“We introduced new ticket machines to give our passengers more choice and flexibility but even we have been surprised at how quickly they have moved away from using notes and coins for even quite small purchases like a £1.50 single ticket.
“What we have seen is in line with a national trend as more and more consumers move away from carrying cash altogether.
"Where this helps us reduce costs we pass that on to the customer – for example this year we have frozen the price of travel with a Pop Pay as You travel, where you can save 30p on a single ticket and 40p for all day travel.
“We will continue to provide the option of cash payment at machines because some people still want to use notes and coins, but we do save from having less cash flowing through and stored in ticket machines and spending less time handling it.
“I would encourage people to save time and money by getting a free Pop Pay as You Go, or just save time by using a contactless card to pay.
"Either way you never need cash to travel on Metro again.”
Credit and debit cards now account for 56% of revenue from Metro ticket machines, and accounted for 48% of all transactions by December 2017.
Figures released by Nexus also reveal that 66% of those transactions are by people using contactless cards, while 94% of students use credit or debit cards to pay for Metro travel.
It has also been revealed that 75% of Metrosaver weekly, four-weekly and annual season tickets are bought with cards, while 59% of older and disabled people buying the £12 annual metro Gold Card use credit or debit cards.