A pedestrian was seriously injured Monday evening when he was struck by a commuter train in Northern Virginia, the Prince William County police said.

The injured person was struck near the Woodbridge station by a Virginia Railway Express train headed for Fredericksburg, according to the commuter line. The train, No. 311, is scheduled to leave the Lorton station for Woodbridge at 5:56 p.m., according to the system’s timetable.

A spokeswoman for VRE described the injured person as a trespasser on railroad property. Lucy P. Gaddis, the spokeswoman said it was important for people to understand the danger of walking on or near railroad tracks.

Details of the injuries were not immediately available. Prince William County police said the pedestrian appeared to be a man. He was walking along the tracks when struck near Railroad Avenue and Dogues Trail.

The site is about a half-mile from the station. The train was presumably reducing speed at that point, although its exact speed was not known.

This story has been updated.