A female grizzly bear has been struck and killed by a Canadian Pacific train in Banff National Park.
It happened near Lake Louise on Saturday evening, Parks Canada officials said in a written release.
The adult bear's two yearling cubs were found nearby the following day, officials said. The bears had been seen in the Lake Louise area last year and had recently come out of their den.
A late spring has delayed the growth of higher vegetation, drawing many bears into the valley bottoms in search of food and easier travel routes.
Park officials will try to keep both orphaned cubs in the Banff eco-system over the long term. To minimize stress on the young animals, they will not be captured or tagged, officials said.
"Their chances of survival aren't that good but there is still a chance. We've had bears, orphaned cubs, survive before and they're quite adept at finding enough food and foraging. But what they really lack is mom's protection," said Hal Morrison, an expert with Parks Canada.
Grain from passing trains, which is known to attract bears, was not found on the tracks or in the bear's stomach, officials said.
Canadian Pacific and Parks Canada are working together on a $1-million research project aimed at finding ways of reducing the number of bears killed on railway tracks, officials said.
The Alberta government designated grizzly bears a threatened species last summer in an effort to better protect the animals.