GP20 Diesel Locomotive

Prototype Information

EMD introduced the GP20 in November 1959. The model countered high-horsepower threats from ALCO and General Electric. Development followed Union Pacific’s mid-1955 road tests. UP had successfully turbocharged its own GP9 fleet. The GP20 used a new turbocharged, 16-cylinder 567D2 engine. It delivered 2,000 horsepower. This was EMD’s first four-axle production locomotive with a turbocharger. The design gave an 11 percent power boost over Roots-blown models like the GP18. Railroads maintained faster schedules with fewer units.

EMD built 260 GP20 units between November 1959 and April 1962. Eight Class I railroads bought them. Western Pacific took the first unit. The Atchison, Topeka and Santa Fe was the largest buyer with 75 units. A prominent exhaust stack and a hood bulge distinguished the GP20. The model helped start second-generation dieselization. Most lines chose low-nose short hoods for better crew visibility. Great Northern and Western Pacific specified high short hoods. The robust units served major carriers for decades. Many later moved to short lines or preservation.