About 70 Minnesotans boarded their own Amtrak train car Friday morning, bound for Washington, where they'll join thousands of other Americans in a demonstration on Sunday demanding that President Obama step up efforts to curb climate change, and in particular to block the Keystone XL pipeline.

Riders on the "Earth Train," which got a flash-mob-style sendoff, include novelist Louise Erdrich, humorist and performer Kevin Kling, and musicians Simone Perrin and Prudence Johnson. Also aboard are Rep. Frank Hornstein, DFL-Minneapolis, chairman of the state House Transportation Committee and a member of the House's Energy Policy Committee, and environmental activists.

Organizers chartered the train car because Amtrak claims it is 17 percent more energy efficient than auto or plane travel. Environmentalists say that air travel creates one of humanity's largest carbon footprints.

The Keystone pipeline system carries oil from northeastern Alberta to destinations in the United States. The XL portion is a controversial proposed extension.

The train was to arrive in Chicago Friday afternoon, and riders were to board another train for an overnight ride to Washington.