Amtrak's San Francisco Zephyr, led by a Southern Pacific freight diesel, climbing high above the North Fork of the American River towards the summit of California's Donner Pass, November 1973. The train is passing a location known both as Rocky Point and Casa Loma. Civil engineer Theodore Judah surveyed much of the route over the Sierra Mountains in the 1850s for the nation's first transcontinental railroad. Completed largely through the efforts of Chinese laborers in the 1860s, the route remains an important link in the nation's rail system. In 2008, Trains selected this image as one the "100 Greatest Railroad Photos" ever published in the magazine.