Amtrak's eastbound Sunset Ltd. passes under the SP westbound main east of Tucson near Vail, AZ on Mar 30, 1974. SP-painted, but soon to be AMTK-owned FP7s held the lead position on the Sunset until enough of Amtrak's first new power, the SDP40F could be built to take over. Southern Pacific 6461, their highest numbered FP7 would become AMTK 123. The bridge above was built for the El Paso & Southwestern and carries mostly westbound traffic, while the lower route handles eastbounds.
