Reported sex crimes in the subway have been on the rise, with police and the MTA encouraging more victims to come forward. That, according to the NYPD, helped catch one man in the act, thanks to a transit worker who was fleet of foot. NY1 Transit Reporter Jose Martinez filed the following report.

Transit worker Darren Johnson retraces his steps on an escalator in the station at Lexington Avenue and 63rd Street.

A day earlier, the 49-year-old station cleaner sprinted up 106 steps on two escalators and a staircase to catch a creep who allegedly groped a woman on a subway platform.

"I have a daughter and I just felt like, you know, there's no way I can let this guy get away," Johnson said.

Police say the 25-year-old victim was waiting for an elevator when she was pawed from behind by a man who reached into her pants before fleeing.

That's when she encountered Johnson.

"I was going downstairs, and I was walking toward the front of the northbound train, and a young lady came up to me yelling, 'Stop him, stop him, stop him!" Johnson recalled.

The chase through one of the deepest stations in the transit system ended when Johnson caught Leonardo San Juan Godinez, 20, near the station's token booth.

"When he got upstairs, he saw two TA workers sitting down and he probably thought that they were undercover cops. So he slowed down," Johnson said.

Johnson said he held Godinez for 15 minutes until police officers arrived and charged the alleged groper with forcible touching.

"15 minutes seemed like 50 minutes," Johnson said.

The incident comes amid new awareness about pervy behavior in the subway.

A video went viral this week of a woman berating a man, who she said was fondling himself on a train.

Police say riders need to be careful about confronting perverts.

"Not encouraging that they self-engage on a subway car or on a subway platform," Police Commissioner Bill Bratton said. "Seek out the conductor or the train operator to summon the police."

Or as in this case, a worker on the platform.

"28 years on the job, I've seen a lot, I've heard a lot," Johnson said. "So I just want to be on top of things."

Wednesday, he certainly was.

"The oppressive heat, the conditions — he's a hero," said Derick Echevarria, the vice president of the Transport Workers Union Local 100. "He did what needed to be done."

And after charging up all those stairs, Johnson — who says he suffers from a bad back — says he's done with the heavy-duty workouts for a while.