Click on the rusted metal cover of the construction shaft at Donner Summit to descend into the summit tunnel. Click on hotspots to proceed from there, exploring the tunnel exits in both directions
After nearly five years of construction, in often abominable conditions, the Central Pacific Railroad broke through the summit of the Sierra Nevada at Donner Pass in the spring of 1868. The 1,659-foot Summit Tunnel (also known as Tunnel #6) was the most difficult engineering challenge of the Transcontinental Railroad. There were four crews of Chinese laborers working to blast out the tunnel from the granite rock: one crew working at each end, and two crews working toward each end, starting from a shaft built down from the mountaintop into the center of the tunnel. This route through the summit has been replaced.
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