The famous Tehachapi Loop is located in the Tehachapi Mountains of California and is a spiral loop on the Union Pacific Railroad (originally built by the Southern Pacific Railroad in the 1870s). The loop allows trains to manage a significant elevation gain over a relatively short distance. What makes it particularly famous is that long trains (over 4,000 feet) can actually pass over themselves as they navigate the loop. An average of 36 trains per day pass though here. The Tehachapi Loop has a 2

A BNSF freight crosses over itself at tunnel 9 and then we see the RB&BB Red Unit circus train. From the Pentrex show "Southern California Rails" https://rfd.video/SoCalRails | Railfan Depot

A southern Pacific heavy mixed freight descends Tehachapi Loop. A set of Santa Fe light engines waits its turn. From the Pentrex show "Cajon Pass & Tehachapi Loop" https://rfd.video/SoCal | Railfan Depot