Every day, trains climb a steep mountain corridor between the southern boundary of Glacier National Park and the northern boundary of the Great Bear Wilderness.

The corridor is at the heart of the continent's wildest landscape, and it is prime bear habitat. In some 24-hour periods, up to 42 mile-long trains use the line. Every once in a while, a grizzly runs or wanders onto the tracks and is hit by a locomotive.

The threat to the grizzlies has fueled a dispute between the railroad, which says it has done all it can to protect the bears, and some wildlife experts, who say it should try harder. At least 32 bears, including nine cubs, have been killed by trains since 1980. Three died last year.

Dr. Chris Servheen, coordinator of the Grizzly Bear Recovery Plan for the U.S. Fish and Wildlife Service in Missoula, surmises that the tracks have claimed a disproportionately high number of grizzly cubs because the long trains split family groups. The trains are high enough for the bears to see one another beneath them, and "we think the cubs bolt across to get to mom and can't go fast enough to avoid getting killed," Servheen said.

The number of killed grizzlies is likely to be higher than reported, experts said, because some may be knocked off the trestles, killed at night or remain uncounted because they have wandered away to die.

The Burlington Northern Santa Fe Railway, which operates the line, says it has taken numerous measures to prevent the grizzlies, a federally protected species, from being killed. The steps include reducing grain spills that attract the bears and cleaning up the spills that do occur, removing dead animal carcasses from the tracks and, in some places, installing electric fences.

The railroad says it is impossible to stop the killings completely, and it has applied for a federal "take permit" to legalize its actions.

"The railroad has taken very effective steps," said Philip Crissman, director of the Great Northern Environmental Stewardship Area in Kalispell, a group that helps the railroad reduce bear deaths. "Can we totally stop it? That's wishful thinking."

Some wildlife experts, however, are outraged. "If I applied for a permit to kill bears, they'd laugh in my face," said Dr. Charles Jonkel, a grizzly biologist who is president of the Great Bear Foundation in Missoula. "If I killed one, I'd get a $10,000 fine and a year in jail."

Poaching is different from killing a bear accidentally, Servheen said. "The railroad has made a lot of progress. It's not like they are trying to kill bears."

Jonkel was deeply critical of the railroad when it spilled a large amount of grain in 1985, and trains killed at least eight grizzlies. He said rail executives informally agreed then on a 15 mph speed limit. Company officials deny any such agreement and say that the limit is now 25 mph, the lowest speed for the trains to travel safely.

Lane Ross, a BNSF trainmaster in Whitefish, said speed does not really matter. "A grizzly bear is not afraid of a train," Ross said. "If one runs out in front of you, you're going to hit it, whether you are going 25 or 60."

Part of the problem is that the tracks have become much busier. Up to 42 trains a day pass through, compared with up to 35 in the 1990s. Railroad executives say the corridor is so critical to interstate and international commerce that when an avalanche blocked it this year, trains were backed up to Minneapolis to the east and Seattle to the west.

The success of the Endangered Species Act has also meant an increase in bear numbers -- and more bears on the tracks. Grizzlies are reclusive and difficult to count, but their numbers in the area are roughly estimated at 500.

Railroad aides concede that they were originally lax about grain spills. In 1985, workers buried the spilled grain. Wet from snow, it fermented, and the rich aroma attracted many black and grizzly bears. Many bears became drunk and tottered out to the tracks.

Jonkel said he believes that the spill set the stage for future deaths. "The mother grizzly bears teach their cubs, and they keep coming back, even if it's gone," he said.
Bear experts at the state's Department of Fish, Wildlife and Parks have installed motion-activated alarms, "critter gitters," at the ends of train trestles over steep valleys. The alarms emit high-pitched shrieks, trying to keep bears away. Despite the efforts, bears continue dying.

"We are asking people to provide us with ideas on ways to prevent collisions," said Tim Bodurtha, the biologist at the Fish and Wildlife Service who is writing the plan. But officials expect the railroad to have its "take permit" by next spring.