A grizzly bear sow and two cubs were killed near Glacier National Park when hit by trains/NPS, Andrew Englehorn file photo from 2015

Three grizzly bears, a sow and her two cubs, were killed when trains ran into them near Glacier National Park.

In years gone past there were times when trains would run into bears that had been attracted to the train tracks that run south of the park by grain spilled from passing trains. This time, according to Montana Fish, Wildlife and Parks officials, there were no obvious attractants that lured in the bears.

The three were killed in separate collions in the predawn hours of June 6 just about two miles east of Marias Pass. The 232-pound sow, which had been captured in the national park in 2000 as part of a research project, was hit about 4:19 a.m. The two yearling males, each weighing approximately 65 pounds, were later struck by a separate train near the same location, according to a FWP release.

Officials did not specify in their release whether freight trains or Amtrak's Empire Builder hit the bears, and a phone call Tuesday was not immediately returned.

Montana officials have worked with agencies and railroad companies over the years to minimize grizzly bear mortalities along travel routes. These preventative measures include reducing attractants.

The Northern Continental Divide Ecosystem is home to more than 1,000 grizzly bears. The NCDE is a designated grizzly bear recovery zone that spans Glacier National Park, parts of the Flathead and Blackfeet Indian Reservations, parts of five national forests, and a significant amount of state and private lands.