Once emblematic of urban disorder, the subways have been a focus of renewed efforts, drawing significant resources for what Deputy Inspector Edward O’Brien called “a cat-and-mouse game.”

Teams of officers, dressed casually, follow tips from riders or transit personnel and fan out across cars. “They know we’re out there,” said Inspector O’Brien, who heads special operations for the Police Department’s transit bureau and who was on the train in plainclothes when other officers moved in to arrest Peppermint and Butterscotch. “They’re stepping up their game to a certain degree.”

Some arrests for dancing have prompted altercations, including a young woman who tried to bite an officer and an 18-year-old man found with a stun gun. But while the turnstile-jumpers or vandals of decades past were often tied to violent crimes, there is little evidence connecting dancers to deeper misdeeds in the subway system. About a fifth of the dancers arrested this year had open warrants, the police said, though few were for serious offenses. Peppermint, Butterscotch and others have typically been charged with reckless endangerment or disorderly conduct. (Their real names were not released because their cases were later sealed.)

Many dancers look to the subways as training grounds for their acts, hoping to eventually take their talents to higher-profile venues, such as clubs, weddings or open-space hubs like the plaza outside the City Hall station. But even outdoor performances can prove to be a problem: Earlier this month, a team known as Waffle (We Are Family for Life Entertainment) was chased from Union Square by a plainclothes officer. The crackdown has unsettled the group’s second-youngest member, the 8-year-old break-dancer Marc Mack, who aspires to join the police. “I want to be a cop that will let people dance,” he said.

On a recent Friday, dancers shooed riders from a portion of an L train car, planting their amplifier on the floor like an underground flag. “Clear the middle for your safety!” Kennedy Noel, 18, said, adopting the cadences of a transit announcement. “We have no insurance!”