Donner Summit Railroad Tunnels abandoned tunnels from the first transcontinental railroad route through the Sierras. Just below Donner Peak in the northern Sierra Nevada mountain range in California lie the remains of the tunnels and snowsheds constructed for the first transcontinental railroad route. In the 1860's, the Central Pacific Railroad, in a race against Union Pacific, sought to complete the first transcontinental line. The heavy snows of the High Sierras required the construction of several miles of tunnels and snowsheds along the mountain pass, constructing 15 tunnels in all. (The difference betwee ...