Public officials have been quick to criticize the planned closure of 164 subway token booths as posing a danger to riders. After a string of violent run-ins with passengers, however, some employees of New York City Transit say they’re worried about their own safety, too.

The Metropolitan Transportation Authority, NYC Transit’s parent agency, is road-testing a program that transforms token-booth clerks into roving “customer service representatives.” Those agents patrol platforms and linger near turnstiles, offering directions, picking up litter, and showing passengers how to properly swipe MetroCards.

So far, NYC Transit considers the program a success. Fourteen agents have been placed in 10 stations since May. One agent, Maria Davis, even saved a life, by radioing the subway command center when a passenger fell onto the tracks.

Another of the agents, Derek Pimble, 42, is a prime example of how the program is supposed to work. After 15 years as a clerk for the MTA, he now stands beaming at the Fulton Street station, scanning the crowd for befuddled faces. He leaps into action when a MetroCard is rejected or a customer needs help finding a train to Sheepshead Bay.

“This job fits me,” Mr. Pimble said.

He concedes, though, that it helps to have a backup person in the booth – a position NYC Transit eventually plans to eliminate. “If customers get angry, they can’t get to the person in the booth,” Mr. Pimble said. Without that person, he said, “it’s going to be rough.”

Other transit workers agreed, expressing particular concern for female agents, some of whom will be asked to patrol stations alone at night, with only a radio for protection.

“You don’t know who you’re going to deal with, especially if you’re female,” one maintenance worker, who declined to be named, said. “The glass, the passengers cannot cross. But outside the booth, you’re open to everything: attacks, crazy passengers. At least I have a broom.”

Even those who work behind the glass sometimes get hassled by customers – or worse. While subway crime reached a historic low last year, the number of assaults rose 9 percent from the number in 2003.

A station agent in the Van Siclen Avenue station in Brooklyn, Patrick Reilly, was almost one of the casualties. According to Transport Workers Union Local 100 and an internal staff newsletter, Mr. Reilly chastised a “swiper” trying to peddle rides off a MetroCard. Later, when Mr. Reilly left the station for lunch, several of the swiper’s cohorts chased him down, forcing him to take refuge in a deli.

The situation is surprisingly common, a longtime agent, Andreeva Pinder, said. She now serves as division chairwoman for Local 100’s station department. Many altercations arise after clerks confront swipers, who sell discount rides using unlimited cards or bend the cards to trick turnstiles, she said.

“If there’s a swiper in the station and I pick up the emergency phone, they know what I’m doing,” she said. “Once the perpetrator becomes aware that you made that call, your life is in jeopardy. There are a lot of maniacs out there.”

She herself was attacked on the job several years ago in the 14th Street station, when she confronted two teenagers who jammed a turnstile, Ms. Pinder said. One of the youths pushed her, she said, and another jumped on her back. “I never even saw it coming,” she said.

Her office handles worker’s compensation claims for the union. “We’re constantly having people assaulted down there,” she said. While neither the Police Department nor NYC Transit keeps stats on worker assaults, Ms. Pinder estimates that she’s received at least 10 claims from workers assaulted by passengers this last year alone. “At least 10 if not more,” she said.

The city’s public advocate, Betsy Gotbaum, shares the union’s concerns.

“The MTA already puts many workers in dangerous situations,” she wrote in an e-mail. “Taking workers out of token booths and making them roam subway stations will exacerbate the problem.”

An NYC Transit spokesman, Charles Seaton, said he seldom hears of assaults on agents.

“It’s not common at all,” he said.

When the pilot program started, agency officials did look into the safety issue, he said, but were reassured because customer service agents won’t handle any cash. So far there have been no incidents, he said.

“Once you take away the money, you take away a large incentive for any sort of assault,” Mr. Seaton said.

He points out that other workers, such as cleaners and maintainers, already work outside the booth. The agency has also proposed redesigning administrative offices in stations so that riders, and workers, will be able to see the staff now hidden within.

And while the station agents won’t be armed, he said, “They’re not supposed to confront unruly passengers.”

That advice didn’t help one clerk who said she was assaulted last week at the Canal Street number 6 station. For no apparent reason, a rider allegedly pushed the woman down the stairs as she was coming to work. The clerk, a 22-year transit veteran who prefers to remain nameless, now sits in a booth in the Herald Square station with her arm in a sling. The plan for roving agents is “a lousy idea,” she said, adding, “I’m just glad I’m retiring soon.”