Atlas Master Series Silver N Scale SD45 Locomotive

During the 1960s the demand for high HP locomotives drove EMD and competitor GE to continue to push the limits of locomotive design. During the time when 3,000 HP 16-cylinder prime movers were the norm, EMD made the decision to introduce a 20-cylinder, 3600 HP design. Introduced in 1965, the SD45, with its distinctive flared radiator design, was purchased by many major US railroads, totaling over 1,200 units until the SD45-2 replaced it in the EMD catalog in 1972.

The SD45 did have some teething problems, most notably crankshaft failures. EMD did provide a means to remedy this issue, but some railroads chose to derate the SD45 to 3,000 HP, or in some cases replace the prime mover with the 16-cylinder 3,000 HP as utilized in the the SD40-2.

Most railroads decided that the extra 600 HP was pushing the limits of the 645 prime mover and preferred the reliability of the 16-cylinder design. The SD40-3 proved to be the best choice for many railroads. It would take a new design, the 710 series prime mover first features in the SD50, for EMD to reach past 3,000 HP again.

Many units are still in service today, most being rebuilt as mentioned. Some did retain the stock 20-cylinder prime mover, a beefed-up engine block mitigated crankshaft failures. Quite a few examples exist in museums, proving that despite some problems the EMD SD45 remains a popular locomotive.