Perched atop craggy bluffs in a beachside city north of San Diego, a railroad line offers passengers a sweeping view of the Pacific Coast. But the ground beneath it is crumbling.

No one denies the problem, but a fight over how to solve it highlights a broader challenge, and a worrisome reality, for California residents: how to adapt to climate change that threatens coastal living, a way of life that has long defined the state’s identity, from its economy to its culture.

The segment of track on the bluffs in Del Mar, Calif., connects San Diego to the rest of the state and the country, and is part of one of the busiest intercity passenger rail corridors in the nation. But the bluffs are eroding rapidly, and the track in some places is now only a few yards from the cliff edge.

Officials and residents in Del Mar and nearby communities broadly agree that the tracks need to be moved, but argue over where they should go. The debate has slowed progress, even as climate change accelerates the risks to the bluffs and the rail line.

On Friday, local representatives on the board of the county’s regional planning agency — the San Diego Association of Governments — voted to narrow the potential alternatives to four options, down from more than a dozen that were assessed in a recent report. But a final decision remains far off.

“It’s at a dangerous point, and with all the bureaucracy involved, it makes us wonder whether it will even be in our lifetime before it’s solved,” Barbara Myers, a former Del Mar school board member, said of the problem. She lives near the proposed location of a tunnel entrance to relocate the rail line, and she worries about toxic fumes or the possibility of street collapses.