In Montreal, I can count on the sidewalks being cleared well enough within 48 hours of a big storm and sort of cleared within 8h (< 2" snow, at least 16-20" wide path, basically one pass of the sidewalk plows.)
There have been weeks at a time where I've had to walk in the street because the sidewalks were just inaccessible or sheets of ice, which makes proximity to the train station all the more important.