The clip, posted on social media on Tuesday, captures the passenger – wearing a Hawaiian shirt and a single earphone – crouching on the back of an L train as it travels between the city’s 40th Street and 46th Street stations, while the train remains in motion.

Inside the car, stunned riders filmed the stunt, added a Spider‑Man theme song to the footage and shared it with the caption “Only in Philly,” prompting a wave of disbelief and criticism from fellow commuters.

SEPTA police captain Marc Pasquarella described the act as “insane” and “extremely dangerous,” warning that a fall could result in serious injury or death and expressing concern that the video could inspire copycat behavior.

SEPTA spokesperson Andrew Busch confirmed that no injuries were reported in the incident, but said investigators are actively working to identify the individual seen in the video.

Authorities reminded the public that subway surfing carries significant hazards, including the risk of electrocution on electrified tracks, slippery or unstable surfaces, and high‑speed impacts, citing recent New York incidents where a 16‑year‑old survived a beam collision and a 14‑year‑old died after riding atop a train on the Williamsburg Bridge.

The Philadelphia episode adds to a growing pattern of reckless behavior on transit systems and may lead SEPTA to consider stricter enforcement measures or public safety campaigns to deter similar stunts.