coils on the walls of the U-shaped channel in which the train runs.

At speeds of more than 90 m.p.h., the train levitates and zips along, four inches above its guideway. At lower speeds, it runs on rubber wheels.

Central Japan Railway hopes to eventually build a $100 billion maglev line between Tokyo and Osaka, but it only has constructed an 11.4-mile test track so far.

China, using German technology, operates a 19-mile-long maglev train line in Shanghai.

The Northeast Maglev, the American company formed in 2010 to bring the Japanese technology to the United States, hosted Tuesday's lunch gathering on the 45th floor of the Comcast Center, with Comcast chief executive Brian Roberts offering his support in a brief telephone cameo from Los Angeles.

Those attending included Lt. Gov. Jim Cawley, CityCouncil President Darrell L. Clarke, Deputy Mayor Rina Cutler, state legislators, and business, academic, and civic leaders.

Former Democratic U.S. Sen. Tom Daschle, now a Washington policy adviser to law firm DLA Piper, chairs the advisory board of the Northeast Maglev, and told the Philadelphia audience that "for a long time, we've heard people say it's impossible, but now it's been done. Now it's real."

Other advisory board members include Rendell, former Republican Govs. George S. Pataki of New York and Christie Whitman of New Jersey, former U.S. Transportation Secretaries Mary Peters and Rodney Slater, Kevin Plank, founder of Baltimore-based sportswear manufacturer Under Armour Inc., and former Northwest Airlines chief executive Douglas Steenland.

The company says a maglev line will require substantial federal funding as well as private investment.

The chief executive