Off the Rails

I can’t think of a better local adventure than exploring the abandoned 140-mile (225km) San Diego and Arizona Railway that connects the Pacific Ocean to the Imperial Valley. Starting at the beach, the railroad courses through sage scrub along the coast to the chaparral in the foothills. Then to the High Desert where it dives down steep canyons to the Sonoran Desert below.

Besides the interesting countryside, the rails cross 57 bridges, including the largest wooden train trestle in the world. There are also 17 tunnels on the tracks as they descend 3,600...