X-Nico

Alternator

Although ac traction motors are emerging for very heavy drag service, particularly in western North America, and its supply of Powder River Basin coal to other areas of the U.S., the simpler dc traction motor system remains the most popular, with Union Pacific alone having over 1,500 current model SD70Ms with dc traction motors (plus an additional 1,000 SD70MACs with ac traction motors).

see also