One can take for granted how easy it is to travel the length of California, but before 1876, the way to and from Los Angeles and the Bay Area had a mighty obstacle: the Tehachapis mountain range running east-west in the southern San Joaquin Valley, between the Sierra Nevada and the Coast Range.

The construction of the Southern Pacific Railroad line through Tehachapi opened up travel between two major California cities in the north and south. It would become vital to the growth of Los Angeles and remain an important part of Tehachapi’s history.

Before its construction, a stage line operated from the railhead at Caliente to San Fernando, but the Tehachapis blocked the way for further southern travel.

Work on the rail line started in 1874 by civil engineers William Hood and J.B. Harris. It was built by Chinese immigrants, on a 2.2 percent gradient route to Tehachapi’s summit. To get the railroad over the mountains, Hood and Harris plotted a route across the Tehachapi Pass, the lowest and easiest pass.

The Southern Pacific Railroad later was extended to Mojave and across the Antelope Valley, reaching Los Angeles through Soledad Canyon and the San Fernando tunnel.

The Southern Pacific Railroad, which monopolized California’s railroads at this time, eventually found a rival in the Santa Fe Railway. Eyeing a line that would cross the Tehachapis from Bakersfield up to Tejon and Chanac Creeks, Santa Fe and Southern Pacific would come to an agreement in 1899 that let Santa Fe trains use the Tehachapi grade. The Santa Fe line no longer needed to be built.

More recently, in 1996, Union Pacific absorbed Southern Pacific, and Burlington Northern Santa Fe succeeded the Santa Fe. Today, the two continue to operate the Tehachapi line.

The track hasn’t changed much since it was built more than 140 years ago. It’s still one of the busiest runs of single-track railroads in the continent, with about 50 trains a day on the famous Tehachapi Loop.