Ac traction gets on track

摘要

In the 1940s, dc traction replaced the steam engine as a source of train propulsion, and it has ruled the freight transportation industry ever since. But now, high-performance ac-traction systems, with their unprecedented levels of pulling power and adhesion, are becoming increasingly common on America's freight railroads. In thousands of miles of demonstration tests, today's ac-traction systems have outperformed traditional dc-motor driven systems. Major railroad companies are convinced enough of the benefits of ac traction to have integrated it into their freight locomotives.