Swipe cards may replace tokens on MBTA buses and trains by next year.

Three token machines sat idly at the back of the Harvard Square T station yesterday, as a dozen people waited nearby for the collector to take their money.

But if a Massachusetts Bay Transportation Authority (MBTA) pilot program succeeds, tokens could be completely replaced by machine-vended “smart cards” as early as next year.

The swipe cards, which are modeled on the token-free fare systems in New York and Washington, D.C., will begin a trial run on the Silver Line starting this January, said Lydia Rivera, an MBTA spokeswoman.

The Silver Line runs buses from downtown Boston to Dudley Square.

“We’re confident this is an excellent mode of payment, but we’ve learned to test something prior to making a complete change,” Rivera said.

In adidtion to tokens for single rides, T stations currently accept monthly subway passes and other bus-subway combination tickets.

If the MBTA pilot is successful, these tokens and passes would be replaced by a swipe card system, which would allow riders to purchase cards and add value to them at T station machines.

It will cost $160 million to upgrade the vending machines and turnstiles for the new cards, according to Joe Pesaturo, another MBTA spokesman.

“It’s fair to say the system is inefficient. It doesn’t come as a surprise,” said Pesaturo.

The Boston subway system is the oldest in America; its first station, Park Street, opened in 1897.

This break with tradition won’t just affect customers. The 325 employees who currently distribute tokens and make change will be converted into customer assistants.

“[The workers] will be out of their contained areas, up on their feet and mobile,” said Rivera.

“Collectors will be more like ambassadors to direct customers to [their] destinations,” she said, although she noted that training has not yet begun, and some employees would likely choose not to continue working.

A token collector at the Harvard Square station declined to comment on the changes yesterday, citing union policy.

Some customers remain skeptical that the collectors will be able to make the switch to the other side of the window.

Bill Wagner, who works at a Harvard Square construction site, takes the subway every morning from Dorchester, sometimes early enough for the 5:10 a.m. train.

“I never talk to [the MBTA workers],” Wagner said. “On the intercom they’re all right...[but] we don’t interact that much.”

In contrast, Pesaturo called the new function of the token collectors an “integral part of the plan” to redevelop the MBTA. He said it was important not only to assist customers, but to “serve as another set of eyes” to monitor safety conditions.

In September, two teenagers were injured in separate fights on the Red Line—one with a machete at the Fields Corner station and the other aboard a train.