The EMD SD45u is a was a rebuild from EMD SD45 diesel locomotives that were originally built by General Motors Electro-Motive Division (EMD) originally for the Atchison, Topeka and Santa Fe Railway.
History
Between 1966 and 1974, General Motors Electro-Motive Division (EMD) had built 125 EMD SD45 diesel locomotives for the Atchison, Topeka and Santa Fe Railway.
But there was an issue with the EMD SD45, the locomotives had some teething problems mainly by their massive twenty-cylinder prime movers that were prone to crankshaft failures from the engine block flex. Though it produced 600 horsepower (450 kW) more when compared to the EMD SD40's 16-645E3 prime movers, some railroads that were using EMD SD45 locomotives had felt that the extra horsepower wasn’t worth it, even after EMD strengthened the block to eliminate the crankshaft failures. At low speeds, when tractive effort was adhesion-limited, and thus, the EMD SD45 provided no advantage over the EMD SD40.
As a result of all these issues, the Atchison, Topeka and Santa Fe Railway has rebuilt 115 units into what had became the EMD SD45u. They were all renumbered as 5400-5483 between 1979 and 1989.
The majority of SD45u locomotives had lasted into the days of the Burlington Northern Santa Fe Railway (BNSF).