section_path: Effects on civilization/Transportation/Rail
section_name: Rail
paragraph_text: Rail
  
  Railroads have traditionally employed two types of snow plows for clearing track, the wedge plow, which casts snow to both sides, and the rotary snowplow, which is suited for addressing heavy snowfall and casting snow far to one side or the other. Prior to the invention of the rotary snowplow ca. 1865, it required multiple locomotives to drive a wedge plow through deep snow. Subsequent to clearing the track with such plows, a "flanger" is used to clear snow from between the rails that are below the reach of the other types of plow. Where icing may affect the steel-to-steel contact of locomotive wheels on track, abrasives (typically sand) have been used to provide traction on steeper uphills.
  
  Railroads employ snow sheds —structures that cover the track—to prevent the accumulation of heavy snow or avalanches to cover tracks in snowy mountainous areas, such as the Alps and the Rocky Mountains.