The Midwest Overland Rail Preservation Society has acquired Union Pacific SD9043AC 3568, making it the first SD9043AC to enter preservation. The SD90s were the largest single-unit diesel locomotives ever built. 

Built in April 1997 as Union Pacific 8138, the locomotive was part of a fleet of 309 SD9043ACs delivered to the railroad between 1995 and 1999. Nicknamed “convertibles,” these units were originally designed around an EMD 16-265H prime mover producing 6,000 horsepower. UP instead bought them with 16-710 engines rated at 4,300 horsepower, intending to convert them to the larger engine once it was ready. Those conversions never happened, as EMD ran into delays and teething problems with its new 6,000-horsepower engine.

As a result, UP classified the locomotives as SD9043ACs while EMD classified them as SD90MACs. The UP designation reflects the 4,300 horsepower the units actually produced, versus the 6,000 they were designed for.

UP 8138 served across the system for nearly two decades before being renumbered to 3568 in 2015. Around this time, the SD90 fleet would be stored for lengthy periods at a time, only being reactivated during surges in traffic. The locomotive would finally be retired from the roster in 2021, though it would sit in storage for five more years. 

— Nick Stewart