Now days railroads also use bulldozers and other heavy equipment to clear the right-of-way of drifts/avalanches. It has resulted in some rail-mounted equipment being retired.
Besides using a wedge plow like a Russell snow plow, railroads often use Jordan Spreaders to clear snow on the rails. When the snow really get heavy they call out the rotary snow plows which can clear much deeper drifts of snow by sucking it into blower and blowing it out to one side just like a snow plow used on drivewys. In the Sierra Nevada mountains the snow can be the wet heavy type which is nicknamed "Sierra Cement" due to its high water content making it hard to plow. Also avalances in the mountains are a terror for the railroads due to how much snow can block the rails. That is why in avalance prone areas railroads build snow sheds to allow the snow to roll down the roof of the shed and into the canyon below.
The snow on the rails themselves only causes a problem when it reduces the friction between the driving wheels and the rail to the point that the locomotives slip. Been there. Lots of sand and careful modulation of the throttle (with perhaps a few pounds of independent) are the cure.
Snow depth isn't a problem unless it impedes forward progress. As John mentions, most snow isn't a problem until you start measuring in feet. On a busy line, the more-or-less continuous traffic serves to keep the ROW basically clear.
Busting drifts up to a couple of feet high isn't usually a problem. Same goes for the snow piled up by highway plows at crossings.
In fact, the bigger issue at crossings may well be ice in the flangeways, which can lift the wheels. It takes some freeze-thaw action to cause that problem, which means it's more likely to occur on lesser-used lines.
Other problem that can occur is icing of the brakes on the cars. Ice vs steel isn't conducive to stopping trains...
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Train locomotives do not have a snow plow that they can drop, but many road engines have a fixed pilot in the form of a small plow, at least on the front end. It can clear to a couple of inches above the top of rail. Most normal snowfalls don't present a major problem, and momentum will allow the train to break though small drifts.
When things get worse, though, a railroad can run a dedicated plow train, normally with several engines pushing some form of wedge plow. Some drifts may need several runs before breaking through, and sometimes need to be dug out by hand before trying again. The plow will usually have a flanger blade that can clean between the rails. That blade has to be lifted at each road crossing and turnout by the track foreman. Plow trains are costly to run and generate no revenue, thus used as little as possible.
Snow depth itself is meaningless without knowing the type of snow. Dry fluffy snow (the skier's dream) gets blown away with no effort. At the other extreme is the wet heavy snow that falls just below freezing, and windblown drifts that get packed hard.
Sorry, no simple answer.
John
I am a new rail fan and a fairly new subscriber to Trains Magazine which I thoroughly enjoy. On page 48 of the December 2014 issue there is a great photo of a Vermont Railway train operating in the snow. At what snow depth do train operators generally drop the snow plow and push the snow off the tracks? Thank you.
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