Friends and co-workers on Tuesday mourned the loss of two women who were struck and killed by an Amtrak train Monday night as they sat on railroad tracks in St. Louis.

Olivia Mares, 20, of the 2600 block of Cathedral Drive in the Oakville area, and Jaclyn Landow, 20, of the 2700 block of Wyoming Street in St. Louis, were pronounced dead at the scene around 11:30 p.m. Monday.

Police said the women were sitting on the tracks near where Kingshighway passes over the tracks when they were hit. The area is south of Manchester Avenue. It wasn’t clear why the women were on the tracks.

They were struck by train No. 316, which was coming from Kansas City and was within four miles of its stop at the downtown St. Louis Amtrak station, said Amtrak spokesman Marc Magliari.

They were hit in an area that’s known as a “quiet zone,” where trains do not normally sound their horns at crossings, Magliari said.

“But our engineers can and will blow the horn if someone is close to the tracks,” Magliari said. He couldn’t confirm whether or not the horn was sounded before the two women were killed, as that’s now part of the police investigation.