Each one of those modern locomotives weighs about 150 to 200 tons or more!
Average snow and ice accumulations are not a problem.
In the really deep snow the railroads use snow blowers instead of plows.
THAT blower is huge!
I suppose these were developed early on for the mountain passes. We had a cabin in the Sierra’s at 7200 before escaping Mexifornia. Snowfall between 25-30 feet before the drought years. Then down to 15’. But, no railroads around ;(