One of BNSF's 16,000 ft "combo trains" negotiates over the hogbacks of Pisgah, CA as it traverse arid Mojave Desert. These "combo trains" are two trains that are coupled up together somewhere between Chicago, IL and Kansas City, KS with the permission of an FRA waiver. They'll either run coupled as one to the ports of Los Angeles and Long Beach, or be split up in Barstow for one of the trains to head north towards Northern California . This PSR trend is being used in ordered to reduce the number of crews needed to get freight across the rail system.