New York subway riders will be able to tap and pay the fare starting May 31

New Yorkers routinely grumble about overcrowded subways and having to wait on long lines to purchase or refill their Metro Cards.

The trains aren't about to get any less congested, but paying the fare might get simpler, at least on certain subway lines starting May 31.

That's when New York's Metropolitan Transportation Authority (MTA) will open up the ability to "tap and pay" at subway terminals with a "contactless" credit card from the likes of Mastercard and Visa, and via certain mobile devices. It's all based on technical industry standards that will let you use any compatible card across rival payment networks.

New York passengers are not going to be able to discard their Metro Cards anytime soon.

The tap-and-pay rollout will be limited at first to the 4/5/6 subway lines between Grand Central Station in Manhattan and Atlantic Avenue in Brooklyn for single ride fares, eliminating for now discount fares or timed passes. Buses in the New York borough of Staten Island will also let passengers pay with such cards.

The goal is to cover the entire MTA system by October, 2020.

For its part, Apple has said publicly you'll be able to use Apple Pay on the Apple Watch or iPhone to ride Big Apple subways and buses by summer.

But this is far from a parochial New York City story.

On Tuesday, for example, commuters in the Portland, Oregon, and Vancouver, Washington, area were able to add the digital Hop Fastpass transit fare card to their iPhone or Apple Watch to tap and ride.

Portland and Chicago as well as London, Sydney and Singapore are among the cities in the U.S. and overseas that already accept contactless payments to ride public transportation, with a lot more coming. (To make it happen, the cities have to update their infrastructure).

That's a big benefit to travelers who want to use the same payment methods across multiple cities rather than having to hassle with a proprietary transit card, or even trying to figure out the local fare system.

"If you have a card in your pocket—which is a Mastercard or a Visa or whatever—(or) your mobile wallet, you will be able to go anywhere and tap and pay. That is the ultimate vision," no matter where you are in the world, says Chaiti Sen, vice president, communications, at Mastercard.

According to Mastercard, half of all London Tube and rail riders in London are using contactless payment cards or mobile devices, with cardholders representing over 100 countries.

New York subway passengers would appear to be ready to pay in kind.

As part of a recent Visa survey of more than 1,000 New York transit riders, two-thirds said they've missed a train while waiting in line to reload a transit card, and 83% indicated they had trouble getting their transit card to work at the turnstile. Another two-thirds have left or forgotten funds on a transit card, at an average loss of $35.10.

It remains to be seen how smooth the rollout will go once tap and pay is implemented.

Dan Sanford, global head of contactless payments at Visa, says the experience will be "transformational" for the customer to be able to tap onto transit, with the same card that you use at the grocery store or coffee shop.