Atchison, Topeka & Santa Fe Railway freight train approaching Canyon Diablo, Arizona, at twilight in June 1993. The train is visible only as a streak of light due to the long exposure. The San Francisco Mountains dominate the western skyline in the background, while signals stand over the two mainlines and beside the siding at far right. The green-over-red aspect indicates that a westward train is also approaching from behind the photographer on main track no. 1, the middle track. Main track no. 2 is on the left. Just beyond the signals is a steel arch bridge over the deep canyon. The route, which links Chicago and Los Angeles, now belongs to the BNSF Railway, and is among the busiest lines in the country.