At Frost, just south of Victorville, California, the old Santa Fe mainline has a "natural" crossover in order to have trains orient trains for the left-hand running typical on Cajon Pass, a few miles ahead. BNSF Railway train S-LPCLBA1-06A (Intermodal Stacks; Logistics Park Chicago IL to Pier A Long Beach CA), behind ES44C4 6662 and ES44DC 7272, is seen here heading west and crossing over the other mainline, which is used primarily for eastbounds.