Coastal erosion shut down every rail connection between San Diego County and the rest of the nation on Tuesday, Sept. 8. The closure stranded passengers and freight on the same vulnerable corridor where Del Mar is pursuing a tunnel to move tracks off its own eroding bluffs.

Swells from Hurricane Marie began battering the Orange County coastline Sunday, Sept. 6, forcing emergency closures between Laguna Niguel/Mission Viejo and Oceanside, the New York Post reported. By Tuesday, waves had overtopped the tracks and damaged protective rock placed over the Labor Day weekend, the Orange County Transit Authority said in a news release.

Amtrak's Pacific Surfliner, Metrolink commuter trains and BNSF Railway freight all stopped running through the damaged stretch. No reopening timeline had been set as of Tuesday. Amtrak offered bus bridges between Oceanside and Irvine on Tuesday, Sept. 8, and Wednesday, Sept. 9, with Surfliner trains still running between San Diego and Oceanside.

The 351-mile LOSSAN corridor from San Diego to San Luis Obispo is the county's only rail link to Orange County, Los Angeles and the rest of the country, as the San Diego Union-Tribune reported. Near San Clemente, the tracks sit roughly 200 feet from the water, according to Voice of OC.

This is not the first disruption. High surf in July 2026 shorted out railroad communications and eroded gravel beneath the tracks near the San Clemente Pier, canceling two Surfliner runs. In 2024, a hillside collapse sent debris across the tracks and closed the line, the New York Post reported.

Del Mar's bluff problem

Del Mar faces a parallel threat along 1.7 miles of high coastal bluffs where stabilization projects have been underway for decades. The San Diego Association of Governments (SANDAG) is now in the environmental review phase of a project to move the tracks into a tunnel beneath the city.

SANDAG has proposed three tunnel alternatives. The longest, Alternative A, carries an estimated price tag of $4.4 billion or more, according to a SANDAG update posted by the city of Solana Beach. Two shorter alternatives would route tracks east under Del Mar and San Diego, with tunnel openings near Los Peñasquitos Lagoon and Jimmy Durante Boulevard.

At a March 17 Del Mar City Council meeting, SANDAG CEO Mario Orso and staff briefed the council on the project. Council members pressed for details on pending geotechnical reports and whether those results would shape the final alignment choice, according to council minutes. Orso reaffirmed SANDAG's commitment to working with Del Mar on bluff stabilization.

The tunnel could be finished by 2035, but only if a final design is approved and funding secured. Neither condition has been met.

Nearer-term rail work

A separate, fully funded project is moving ahead closer to home. The California Transportation Commission in July 2026 allocated $214.3 million to SANDAG for the San Dieguito double-track project, bringing total funding to roughly $350 million, the Union-Tribune reported. That project includes a new train stop for special events at the Del Mar Fairgrounds, additional track, pedestrian undercrossings and a replacement bridge over the San Dieguito River. The existing single-track bridge dates to 1916.

"Final design is complete, and the project is currently being advertised for construction bids," a SANDAG official told the Union-Tribune in July. "Construction … is set to begin in early 2027 and is expected to be complete by mid-2031."

State Sen. Catherine Blakespear, D-Encinitas, authored Senate Bill 1098, the Southern California Rail Revitalization Act, signed into law in 2024. The law directs the California State Transportation Agency to prioritize capacity and climate-resiliency projects along the LOSSAN corridor. A working group created under SB 1098 published draft recommendations on June 10 for a 30-day public comment period.

Del Mar resident attorney Shirli Weiss raised concerns at the June 16 council meeting that one working group recommendation could expand environmental review exemptions for rail projects. She said the change could shift oversight of Del Mar's bluffs from the California Coastal Commission to a federal agency, the Surface Transportation Board.

Separately, all COASTER commuter rail service is scheduled to halt Saturday, Sept. 12, and Sunday, Sept. 13, for a previously planned maintenance window. Regular service is expected to resume Monday, Sept. 14.