Honolulu transit officials are working to finish additional court-ordered studies for the city’s planned elevated rail project, even as they prepare to defend the $5.26 billion effort later this summer in federal court against opponents looking to stop the project.

In a new draft report released this week, the Hono­lulu Authority for Rapid Transportation and the U.S. Federal Transit Administration conclude that tunneling under Beretania Street would be "feasible" but still too costly an alternative compared with running an elevated track along that stretch of the city.

The draft supplemental environmental impact statement also found that the railway would have "significant effects on views of and over" Mother Waldron Neighborhood Park as the track passes through Kakaako. However, rail would not "substantially impair" the park’s historic or recreational uses, the draft report states.

The public will have a chance to weigh in on the HART and FTA report during a 4 p.m. meeting July 9 at the Neal Blaisdell Center’s Hawaii Suite.

The studies on Beretania Street and Mother Waldron Park are two of three requirements that visiting federal Judge A. Wallace Tashima placed last year on city and federal transit officials. Those steps were part of a federal lawsuit brought by former Hawaii Gov. Ben Caye­tano, retired businessman Cliff Slater, University of Hawaii law professor Randall Roth and other opponents who maintain city and federal officials did not properly approve the 20-mile rail project, slated to extend from East Kapo­lei to Ala Moana Center.

"One thing we’re very confident on is they did not follow the law," Roth said Thursday during the "Town Square" public affairs show on Hawaii Public Radio.

While Tashima’s ruling in December allowed building to go forward, it halted the fourth and final construction phase until the city addressed the outstanding issues at Mother Waldron Park and Beretania Street. Tashima also required the rail officials to study any cultural sites that could be affected by the transit system.

That study is expected to be completed in July, HART spokes­woman Jeanne Mari­ani-Bel­ding said Thursday.

Tashima would then eventually decide whether to approve the reports, Roth said.

Roth called the transit officials’ conclusions on a Beretania Street tunnel and Mother Waldron Park "predictable" because they would allow the rail project to proceed as planned.

While Tashima’s order called for added study, it did not overturn the rail project as Roth and other opponents had hoped. The suit’s plaintiffs filed an appeal in February to overturn Tashima’s ruling, and the 9th U.S. Circuit Court of Appeals is scheduled to hear the appeal the week of Aug. 12 in San Francisco.