A woman was struck and killed Friday night as she ran onto the SEPTA railroad tracks at the Bryn Mawr station to save her dog from an oncoming commuter train, police said.

The woman, who police described as in her 40s and from out of state, was on the eastbound platform just before 6 p.m. when her black Chihuahua bounded onto the tracks.

Hezekiah Bey, 35, who drives for the Rosemont Taxi Co., said he was standing on the platform near the woman at 5:55 p.m.

Bey said the unleashed dog was excited and turning in circles as a westbound train stopped on the far set of tracks. Another woman joined her in conversation. A few moments later, the dog jumped off the platform onto the eastbound tracks, a few inches below.

The owner followed the dog to the middle of the tracks, where she leaned over and was picking it up.

"She did not have time to get back up, and the train was on her," Bey said. "It was terrible-looking under the train."

The train stopped. The dog came out from under the train, apparently unhurt, and a third woman picked it up.

Bey said he then called 911 on his cell phone.

Lt. Bernard D'Amour of the Lower Merion police said officials were trying to contact the woman's relatives Friday night.

The dog was taken to an animal hospital.

Eastbound commuter service on the R5 Paoli-Thorndale line was suspended until 8:35 p.m. as investigators examined the scene. Passengers aboard the train that struck the woman were shuttled to their destinations by bus, according to a SEPTA spokesman.

With the track just a few inches below the platform, nothing prevents people from walking onto the tracks at that point in the line. Just a few feet from where the woman was standing on the platform is a sign with red background and white letters that reads, "Do not cross tracks."

Contact staff writer Sam Wood at 215-854-2796 or samwood@phillynews.com.