RIVERSIDE – Union Pacific police are reviewing videotape to determine how a female pedestrian was struck by a freight train early Sunday in Riverside and died of her injuries, authorities said.

The incident was reported at 2:45 a.m. Sunday on Union Pacific tracks about 500 yards east of Riverside Avenue in Riverside, according to coroner's and railroad officials.

The victim was pronounced dead at 3:10 a.m. at the accident site. The victim had not been identified as of early Sunday, according to coroner's officials.

The Union Pacific train's engineer saw the woman on the tracks and sounded his horn but there was no way to stop, said Union Pacific spokeswoman Zoe Richmond, who is based in Sacramento.

Union Pacific police were reviewing videotape to determine what happened, Richmond said.

“The investigation is going to depend on the camera on the locomotive,” Richmond said. “We shoot video of everything the engineer sees. The engineer did sound his horn when he saw the woman on the tracks. . . . We don't know why she was on the tracks.”