Jedediah Smith came through in 1827, and John C. Fremont made a scientific observation of the valley in 1844. After Fremont's visit the 49ers crossed the valley via the Old Tejon Pass into the San Joaquin Valley on their way to the gold fields. Later, a better wagon road, the Stockton - Los Angeles Road route to Tejon Pass, followed in 1854. Stagecoach lines across the southern foothills came through the valley along this wagon road, and were the preferred method for travelers before the coming of the Southern Pacific Railroad in 1876. The rail service linking the valley to the Central Valley and Los Angeles started its first large influx of white settlers, and farms and towns soon sprouted on the valley floor. The aircraft (now called aerospace) industry took hold in the valley at Plant 42 in 1952. Edwards AFB, then called Muroc Army Air Field, was established in 1933.