The city’s $5.5 billion rail transit project is facing another legal challenge, this time in federal court.

A group of project opponents, including former Gov. Ben Cayetano, retired state appellate Judge Walter Heen, state Sen. Sam Slom and longtime rail opponent Cliff Slater, filed a lawsuit in U.S. District Court yesterday seeking to invalidate the project’s environmental impact statement and federal government approval.

The lawsuit names as defendants the city, city Transportation Director Wayne Yoshioka, the U.S. Department of Transportation, Transportation Secretary Ray LaHood, the Federal Transit Administration, FTA Administrator Peter M. Rogoff and FTA regional Administrator Leslie Rogers.

Plaintiffs accuse the city of violating federal environmental, historic preservation and transportation laws in preparing the EIS and accuses the U.S. Transportation Department of violating the laws for approving the project.

Gov. Neil Abercrombie approved the EIS as one of his first official acts when he took office in December.

The FTA issued a "record of decision" the following month, an indication that the project meets all the requirements of the environmental review process and which is a step in granting it federal funding.

Federal transportation laws require the transportation secretary to cooperate and consult with other federal agencies and states in developing transportation plans and programs that include measures to maintain or enhance the natural beauty of lands crossed by transportation activities or facilities. The laws allow the secretary to approve projects that require the use of lands of national, state or local historic significance only if there is no prudent and feasible alternative to using that land and the program or project includes all possible planning to minimize harm to the historic site. The suit claims the rail project will adversely affect at least 32 historic sites, including the Chinatown Historic District, the Pearl Harbor National Historic Landmark and Aloha Tower.

Slater said the project also will affect views of historic buildings in downtown Honolulu.

"It will be an immensely intrusive concrete structure," he said.

The lawsuit also claims city officials defined the requirements of the project so narrowly so as to exclude all reasonable alternatives.

City Managing Director Doug Chin said city officials have not yet seen the lawsuit. However, he said, "Because of multiple statements made by plaintiffs to the media over the last couple of months, we know of the basic assertions and are prepared to defend against the lawsuit."

A state judge sided with the city in March in a lawsuit challenging the way the city is conducting a survey of ancient Hawaiian burial sites. The judge said the city does not have to complete the survey of sites along the project’s entire 20-mile route before breaking ground. He said the city may do the survey in phases.