The Tehachapi Loop lets long trains cross over themselves

The Tehachapi Loop is one of those engineering ideas that becomes easier to understand once you picture the problem. Trains are strong, but they do not like steep climbs. To get between the San Joaquin Valley and the Mojave side of the mountains, railroad builders needed a gentler way up.

The answer was a loop. Completed in 1876, the track bends around a central hill so a long train can gain height slowly. A 4,000-foot train can pass 77 feet above its rear cars in the tunnel below. Rail fans get excited here because the train can seem to cross over itself.

The American Society of Civil Engineers gives the wider scale. The Tehachapi Pass Railroad Line included 18 tunnels, 10 bridges, water stops for steam locomotives, and heavy work through granite by about 3,000 Chinese laborers using picks, shovels, carts, and blasting powder.

So the Loop does more than look clever from a viewpoint. It is a reminder of the labor and planning behind California’s north-south rail connections. If you go looking for it, stay with public viewpoints and posted access. Active rail lines are not sightseeing paths.