Page "First Transcontinental Railroad" Paragraph 78

The Central Pacific soon learned that it would have trouble maintaining an open track in winter across the Sierras.

At first they tried plowing the road with special snowplows mounted on their steam engines.

When this was found only partially successful an extensive process of building snow sheds over some of the track to protect it from deep snows and avalanches was instituted.

This eventually kept the tracks free for all except a few days of the year.