Why avalanches roar over this Sierra railroad and the trains never slow down

An avalanche roars down the Sierra Nevada, and the train underneath doesn't even slow down. In the 1860s the transcontinental railroad met snow it couldn't beat: 44 storms in the winter of 1866 and more than 40 feet of snow. Bigger plows and thousands of shovels still lost. So they flipped the problem. Heavy timber sheds covered the tracks, with roofs that continued the mountain's slope, so an avalanche slid right over and kept going. A five-mile test went up in 1867, and by 1869 about 37 miles of railroad ran under wooden roofs. Concrete sheds still do the job today. Sources: • The Transcontinental Railroad: Snow Sheds — https://www.lindahall.org/experience/digital-exhibitions/the-transcontinental-railroad/07-snow-sheds/ • Snowsheds (Sesquicentennial exhibit, PDF) — https://www.donnersummithistoricalsociety.org/pages/SesquicentennialExhibits/sesquicentennialsnowsheds.pdf • Snowsheds exhibit — http://www.donnersummithistoricalsociety.org/pages/exhibits/snowsheds.html