SP piggyback train By Mitch Horner | December 2, 2025 Email Newsletter Get the newest photos, videos, stories, and more from Trains.com brands. Sign-up for email today! Get Updates For a time in the 1950s, Southern Pacific had the most extensive piggyback operations in the land. Here a train bound from Los Angeles to the San Francisco Bay Area climbs Santa Susana Pass near Chatsworth, Calif. Classic Trains coll. Share this article Print Facebook