MARTA has announced a crackdown on people who try to ride trains without paying.

The transit agency says MARTA’s police officers have arrested 538 “fare evaders” over the last six weeks.

“Our fare evasion task force has worked around the clock to focus our attention to those seeking to avoid paying fare at our stations,” Marta Police Department Chief Wanda Dunham said in a press release. “We have watched riders piggyback behind a person when the fare gates open and some even attempt to go over or under the gates.”

Plainclothes officers have been on the lookout for offenders at the agency’s 38 rail stations.

People who are arrested are suspended from MARTA buses and trains for 60 days. People who are arrested and don’t have ID are sent to jail, the press release from MARTA says.