A train driver escaped injury after a rock was hurled through the window of his South Yorkshire train.
British Transport Police officers are appealing for information after the large rock was thrown at a train, narrowly missing the driver.
The incident happened at around 5.30pm on Saturday as a train was travelling under the footbridge that leads from Highthorn Road in Swinton.
A man wearing a green jacket was standing on the bridge and dropped a large rock onto the train.
The rock smashed through the cab window and narrowly missed the driver. He was not injured, but was extremely shaken by the incident.
Investigating officer PC Joseph Robinson said: “This was an incredibly stupid thing to do, and could have resulted in the serious injury of the driver.
“Have you seen anyone doing this, or know who the man in the green jacket might be? Please get in contact.”
Anyone with information is asked to contact British Transport Police, quoting 377 of 10 September.