This photo illustrates the wide variety of power that one can see at the UP North Yard in Denver. Eagle-eyed viewers will notice 11 different types of power, (not including the MOW vehicles) and perhaps some of the oldest power on the roster (GP40M-2 built in 1966), to one of the newest engines (SD70ACe). If you include the former operators of the engines seen in this picture, there are 8 different flags represented by these engines, including Southern Pacific, Milwaukee Road, SOO Line, CSX Chessie, Baltimore & Ohio, Missouri Pacific, Chicago & Northwestern and of course the Union Pacific. The list of specific power includes SD70Ace (UP 8895), GP15-1 (UPY 546, UPY 577, UPY 691), MP15AC (UPY 1425, UPY 1449, UPY 1484), SD40-2 (UP 3138), GP40M-2 (UP 1489), GP40P-2 (UP 1373), SD70M (UP 4676), AC4400CW (UP 7247), ES44AC (UP 7940), AC4400CWCTE (UP 6059), and AC4460CW (UP 7069).