The Central Pacific Railroad first began train services to Donner Pass in 1868 after the completion of the First Transcontinental Railroad across the United States. A new tunnel constructed two-miles (3 km) through virtually solid granite, dubbed The Big Hole tunnel, was later constructed through Mt. Judah in 1925, offering trains better protection from snow storms on the summit. These heavy snow storms and blizzards during the winters often made even train service difficult over the years through the pass, which for a period of time was known as the Overland Route.