Metro plans to allow customers to pay their train and bus fares with their mobile phones by the end of 2019, the transit agency announced Tuesday. The agency is upgrading its fare boxes, fare gates and fare vending machines — adding new hardware that will allow customers to use the same tap-and-go technology with their phones that they use with SmarTrip cards.

The upgrades will be finished sometime next year, Metro said, though it’s unclear how many riders will immediately have access to the system. Each mobile payment platform (such as Apple Pay or Google Pay) must separately work with Metro to ensure that their technology meets the transit agency’s standards for speedy transactions before users of that platform can start using the mobile payment system.