The Massachusetts Bay Transportation Authority expects to complete the T’s switch to an automated fare collection system by May 2021, but will begin rolling it out on a limited basis in late 2019.

The system, among other changes, will mean the end of paying for any T rides with cash. Instead, riders will use a far card, a smartphone app, or a contactless card to tap and board. Riders will be able to reload the fare cards and apps online and at vending machines in all T stations and at select bus stops.

The idea is to speed up boarding and to also make it easier for the MBTA to track and analyze rider data (to in part improve service).

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From a website the MBTA has set up regarding what it calls Automated Fare Collection 2.0, or AFC 2.0: “With shorter lines and reduced boarding times, buses and Green Line trains will move on more quickly. If you travel by bus, you should be able to get where you’re going 10 percent faster.”

AFC 2.0 will be available in full starting May 2020, the MBTA says, and will run alongside the current system for a year. After that, it’s tap and go all the way.