A January 1953 landslide in Humboldt County knocked an 80-ton locomotive off the tracks and into the flood-swollen Eel River, trapping and killing three railroad men inside.

The city of Novato spent millions of dollars redeveloping Grant Avenue and may spend millions more to pave the way for a new shopping mall on Redwood Boulevard.

The city’s investments downtown and Eel River landslides were cited Tuesday as respective reasons why the Marin County Board of Supervisors and a coalition of environmental groups threw their support behind the city’s lawsuit against the North Coast Rail Authority. It’s the public agency that aims to restore freight trains to 316 miles of track stretching from Eureka to Marin and Sonoma counties.

The Marin County supervisors voted four-to-zero in closed session to file a friend of the court brief supporting Novato’s lawsuit, which says the city hasn’t complied with the state and federal environmental law. It will be heard Dec. 12 in Marin County Superior Court.

“We have a $10 million renovation of our downtown … and this is going to be running right there,” said County Supervisor Judy Arnold.

“Are we going to have quite zones at Trader Joe’s and Whole Foods?” Arnold asked, referring to the installation of seamless sections of track that reduce vibration.

Arnold said the railroad authority hasn’t provided enough information about how its operations could impact Novato and what mitigations might be made.

The coalition of environmental groups that announced Tuesday it would file a friend of the court brief include the Friends of the Eel River, Marin Conservation League, Environmental Protection Information Center, Californians for Alternatives to Toxics and the Watershed Protection Network.

“The Eel River canyon is very fragile … it slides like jelly,” said Nadananda, the executive director of the Friends of the Eel River. (Nadananda’s one-word name is Sanskrit for “the blissful sound of the universal energy,” she said.)

The railroad tracks, which opened in 1916 and carried freight for about 70 years, caused numerous landslides into the Eel, Nadananda said. The railroad and logging released so much sediment into the once-pristine river, she said, that the silt load the Eel carries is “15 times greater than the Mississippi.”

Mitch Stogner, executive director of the rail authority, declined to comment Tuesday, because the matter is under litigation.

But the rail authority’s attorney, Chris Neary, of Willits, said that he filed a legal brief that week that calls into question the city’s right to sue the rail authority.

“The city of Novato doesn’t have any right to bring this lawsuit,” Neary said.

He said that, as of Nov. 21, the city had spent $85,000 on the lawsuit.

If elected officials who sit on city council want to sue the railroad authority, “They should do that with their own money, not the public’s money,” Neary said.

Supervisor Charles McGlashan was absent from Tuesday’s meeting of the county board and did not vote.