Burlington Northern Santa Fe’s Denver to Stockton manifest freight works upgrade at Coal Creek Canyon west of Clay, Colorado, on April 21, 2002. The head-end power is already through Tunnel 1 in the background, and pushing on the rear of the westbound train is a pair of EMD manned helpers units. BNSF No. 7321 is a former Canadian National SD40 rebuilt by GEC Alsthom and labeled a SD40-2, and BNSF No. 7165 is a former BN unit built in 1979.