Cops are questioning a suspect Thursday in a shooting that injured an innocent bystander at Penn Station — connecting him to the crime after he allegedly ditched the gun in a trash can at the transit hub, police sources said. 

The suspect was picked up in Brooklyn in connection to the Monday evening rush-hour shooting that left 58-year-old Christopher Farrell with injuries to his leg outside the NJ Transit entrance at Seventh Avenue and West 31st Street, according to the sources. 

The gunman apparently dumped his weapon in a garbage pail near Penn Station after the shooting, and it was recovered the next day at a sanitation transfer station in Red Hook, the sources said. 

The suspect, who may be a local delivery person, was brought into the Midtown South station house early Thursday, according to the sources.

The gunfire erupted around 5:40 p.m. — shortly after the suspect appeared to have asked for some food from another man, 56 — and was “kind of shunned away, and that kind of spills onto the street here,” NYPD Commissioner Dermot Shea said during a press conference from the scene. 

He fired one shot — missing his target, but striking Farrell in the right thigh, cops said. 

Farrell was taken to Bellevue Hospital in stable condition and underwent surgery this week.