A westbound Union Pacific intermodal train flies across Cienega Creek Bridge at Vail, Arizona, on the afternoon of April 22, 2017.

Southbound NS intermodal train P99 flies under the signals at "Glass" just south of Kannapolis, NC, with a newer UP ES44AC up front.

Who's railroad? A UP and BNSF train meet at Caliente on the Tehachapi Pass. Two railroads doing the same job, working together.

From the US 30 overpass.