The L0 series magnetic-levitation train, developed by Central Japan Railway Co., moves along a test track near the control center during a trial run in Tsuru City, Japan, on Aug. 29, 2013. (Yuriko Nakao/Bloomberg)

An investor group hoping to build a high-speed train capable of cutting the travel time between Baltimore and Washington to 15 minutes says in a filing to state regulators that it has lined up more than $5 billion in financial backing.

The commitment is from the Japanese government, which hopes to showcase the technology behind superconducting magnetic levitation or “maglev” trains to an American audience, the company behind the proposal wrote to the Maryland Public Service Commission on Wednesday.

Such trains are capable of extreme speeds, thanks to their frictionless, magnetically-controlled motion above their tracks. The technology has been approved in Japan and is to be rolled out next month on an initial stretch of track that planners hope will eventually connect Tokyo, Nagoya and Osaka.

In addition to the $5 billion commitment from the public Japan Bank for International Cooperation, the private Central Japan Railway Co. has agreed to waive any licensing fees for use of its maglev technology, wrote attorneys for the Annapolis-based Baltimore Washington Rapid Rail LLC.

The details were included in Rapid Rail’s filing Wednesday asking Maryland regulators for the old state franchise rights of the former Washington Baltimore & Annapolis Electric Railroad, a once-busy interurban electric rail car system that linked the three cities in the early 20th century.

“In a back-to-the-future type way, you see that there was already a Baltimore-Washington service that previously existed. . . sort of sitting on the shelf waiting for people to pull it off and dust it off, for us to get back to providing what they had in 1935,” said Wayne Rogers, a major shareholder in Rapid Rail and chairman and chief executive of The Northeast Maglev, a separate Washington-based company backing the project.

A spokeswoman for the Maryland PSC, which regulates “common carriers” in the state, including passenger rail providers, confirmed receipt of the application. The agency will open a case on the application, accept comments from staff and others, and conduct a hearing on whether granting Rapid Rail’s request “is consistent with the public convenience and necessity,” said Regina L. Davis.

Mayor Stephanie Rawlings-Blake’s office welcomed the new details about maglev.

“Because Baltimore provides millennials and empty-nesters with affordable city living, this speedy mode of transportation will provide residents who work in D.C. with a convenient alternative, while also giving tourists throughout the country who visit our nation’s capital easier access to enjoy all of the attractions Baltimore has to offer,” said Caron Brace, a spokeswoman for the mayor. “Ultimately, this would help the local economy, as well as help to grow the city. It could be a game-changer for Baltimore.”

While maglev is a tantalizing technology for high-speed transportation, there are many barriers to its implementation, including concerns over the difficulty of assembling a route, its effect on neighbors and its sheer cost.

The Japanese financing has been hinted at for nearly a year. Prime Minister Shinzo Abe talked up the project to the Obama administration last year. Northeast Maglev said it could count on financing from a Japanese government bank, citing that support as the key difference between its proposal and others in the past that fizzled out with little outside investment and a lack of federal will to assist.

Still, Northeast Maglev did not disclose details about the Japanese commitment until now.

The total cost of the Baltimore-to-Washington leg of the project is unknown and would depend largely on the final route of the mostly underground track, Rogers said, but it would cost at least $10 billion.

Some critics say even that price tag is too low to make maglev a reality.

“Unless someone has all the cash to build the whole system all in one go, or at least in rapid phasing, the whole thing doesn’t make sense,” said Andy Kunz, president and CEO of the U.S. High Speed Rail Association, which supports more conventional high-speed rail systems. “Who is going to come up with the other $5 billion, or probably $10 billion more?”

Kunz said some estimates put maglev costs at five times those of high-speed rail systems that now can reach speeds of 220 mph — like those currently being built in California.

The investment needed to build a maglev line between Washington and New York, the only connection that would make sense for the system, is so huge that it will never get built, Kunz said. He predicted that if the Baltimore to Washington stretch gets built, it will end up like other short-track maglev experiments around the world.

“If this does get built, it’s going to end up looking just like the Chinese maglev, which is almost a joke. People ride it as a novelty, but not for transportation,” he said. “I would really be [angry] if our government forked over $5 billion for this little system to Baltimore” when it could move more people farther distances with the same amount in California.

Rogers said his hope is that the promised investment from the Japanese will spur interest among more investors, eventually allowing the extension of the line from Baltimore to New York.

The Japanese hope the same, and that U.S. commitment to the technology along its busy Northeast Corridor will be copied around the world — creating a new export market for Japan’s rail industry.

The Baltimore Sun