An effort by Peninsula cities to stop California's high-speed-rail project came to a screeching halt Thursday when a Sacramento County judge upheld the California High Speed Rail Authority's environmental-review process for the highly controversial project.

The lawsuit was the second one brought against the California High-Speed Rail Authority by Atherton, Menlo Park and Palo Alto. In the first suit, which required the rail authority to revise parts of its Environmental Impact Report, Palo Alto filed a "friend of the court" brief in support of the plaintiffs.

The three cities, along with several coalition groups, had argued since 2008 that the rail authority failed to adequately review the Altamont Pass before it chose the Pacheco Pass as its preferred alternative for the Peninsula segment of the San Francisco-to-Los Angeles line. The cities had challenged the rail authority's ridership projections for the Pacheco segment and argued that the agency did not adequately describe the project in its program-level Environmental Impact Report (which is broader and more general in scope than the project-specific reviews).

The rail authority's CEO, Jeff Morales, released a statement celebrating the court ruling, citing Judge Michael Kenny's finding that the plaintiff "adequately disclosed to the public how the project would be implemented and described in adequate detail what the environmental consequences of such implementation would be."

"This is an important ruling and is testament to the fact that the Authority is committed to delivering the high-speed rail project in accordance with the law and in partnership with the public," Morales said. "We continue to move forward to start construction this summer and create thousands of jobs in California."

The ruling could be a mixed blessing for the cities. Since the second lawsuit was launched, the project has transformed markedly and the once controversial four-track design has been scrapped in favor of the "blended approach" under which high-speed rail shares tracks with Caltrain on the Peninsula.

The rail bill approved by the state Senate last fall also allocates $1.1 billion for long-awaited improvements to the Caltrain corridor. This will include $700 million for electrification of the popular but cash-strapped system – a project that the agency has been studying for more than a decade. The funding may have been in jeopardy had the lawsuit gone the cities' way.

Last week, state Sen. Jerry Hill, D-San Mateo, proposed a bill that would further lock in the funds for Caltrain.

The ruling is the latest of several notable victories for the once beleagured rail authority. Last year, the state Senate approved by a single vote funding for the first segment of the rail line, which would be constructed in the Central Valley. Kenny's ruling in favor of the authority allows the rail project to bypass another potential delay.