In 1959, the Electro-Motive Division of General Motors began promoting two models that featured a mechanical device previously missing from any EMD locomotive. These models, the GP20 and SD24, were equipped with a turbocharger. While six-axle trucks are common today, there was a time when locomotives with the six-axle configuration were relegated to low-speed drag service because of their mediocre per-axle horsepower rating. All of this changed when EMD turbocharged its workhorse 567-series prime mover. Several Class 1 railroads took notice and quickly ordered SD24s in an effort to tame their rugged operating profiles. Included were Santa Fe, Burlington, Union Pacific, and Southern. After extensively testing turbochargers on Union Pacific GP9s, EMD offered a four-axle turbocharged model, the GP20, to complement its SD24. In the late 1950s, with highway motor carriers making gains in the movement of long-haul shipments, it became important for America’s railroads to increase train speed. While the SD24 handled higher tonnages on mountain grades, the GP20 began speeding time-sensitive freight across the West. Western Pacific ordered the first GP20s, followed by Great Northern, Santa Fe, Union Pacific, Cotton Belt, Burlington, New York Central, and Southern Pacific. Join us as we take an in-depth look at these two innovative models that introduced EMD’s turbocharged two-cycle power plant to the railroad world.
Softbound, 8.5″ x 11″, 156 pages (32 color pages), 346 photos (82 color photos), HO-scale fold-out drawings
GP20/SD24: Turbocharged Duo
Photo may not show actual road number . Please see description for actual road number