It's been a week since a train carrying shale oil derailed, resulting in a crash and explosions that devastated the small Canadian town of Lac-Megantic in Quebec.

François Laplante-Delagrave/AFP/Getty Images

Fifty people are presumed dead. The number of confirmed dead stands at 28.

Transportation workers are moving carefully in and around the site of the derailment, searching for evidence that would help explain what led to such massive destruction.

The chairwoman of Canada's Transportation Safety Board, Wendy Tadros, says it will be months or longer before investigators will be able to draw any conclusions about what happened

The president and CEO of U.S.-based Rail World Inc., which owns the runaway train, has blamed the engineer for failing to set the brakes on the train, which came from North Dakota.


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