Since 2011, NS has purchased over 100 used SD40-2 models from various leasing companies. Many of these "new" locomotives come from many different ancestors, including NS 3454, built as Missouri Pacific SD40-2c 6020 in June of 1979. The first two orders of these units (3216-3220 and 3221-3235), equipped with dynamic brakes, gyralights, and rotary beacons, a departure from standard Mo-Pac equipment practice, were intended for pool service with BN and Rio Grande coal trains, hence the "c" in the model designation. The units were also ballasted heavier (some well in excess of 400,000 lbs), which meant that the Mo-Pac engineers who operated the units were paid slightly higher wages at a time when some roads paid engineers high wages based on more weight on the drivers. The 3216-3235 were later renumbered 6000-6019. Subsequent orders, numbered 6020-6049, 6050-6053, and 6054-6073, did not have the Rio Grande headlight package. In total, MoPac owned 74 of these heavyweight coal-hauling Dash Twos, some of which are still hauling freight nearly three and a half decades after they were delivered.
