A Massachusetts woman was fatally struck by a train in the Bronx early Saturday, police said.

The victim, 22, was on a narrow walkway along elevated tracks when a southbound No. 1 train struck her near West 238th Street and Broadway in Kingsbridge at around 4:30 a.m., officials said.

The train operator told investigators she didn’t see the victim, and only discovered the body while inspecting the roadbed after the emergency breaks kicked in, a source said.

The victim’s body, discovered under the first car, is being held at the Jacobi Medical Center’s morgue while family notification is pending, police sources said.

No criminality is suspected at this time. Officials said they did not know why the woman was walking on the tracks.