Tehachapi Loop is an amazing feat of ingenuity to raise or lower a train a significant elevation in a very short distance. The project was completed in 1876, and has remained largely unchanged today. When the train is going downhill, or generally to the northwest, it begins a descending arc in a clockwise direction. As it goes over a tunnel, it starts a 0.73-mile loop, tightening its spiral to encircle a hillock. As it completes the loop, 77 feet lower, the train circles under itself—through the tunnel that a long…
