The Durango-Silverton Narrow Gauge Branch of the Denver & Rio Grande Western Railroad extends from the town of Durango to the mining camp of Silverton. Built in 1882 through one of the most rugged mountain areas of the nation, its complexity remains a testament to the role civil engineering played in the development of the western United States.
The tracks rise up the sheer, steep Animas Canyon, running along a rock ledge just wide enough to carry the train. The line is used today as a tourist attraction, carrying visitors through the picturesque San Juan Mountains.