Excavation of the Alpine Tunnel began in January 1880. At an altitude of 11,523 feet, it became the first tunnel constructed through the Continental Divide, and was expected to be finished in only six months. However, due to unforeseen circumstances and construction taking place in the dead of winter, the task required nearly two years to complete. Fractured granite necessitated the expense of using over 400,000 board feet of California redwood to support and encase 1,427 feet of the 1,772 foot long tunnel with a total cost of around $300,000..