Stabilization, not tunnel, is first priority for vulnerable bluff-top Del Mar train tracks

Protecting the train tracks on the crumbling seaside bluffs in Del Mar, not building an alternative route with tunnels, should be the region’s top priority, officials said this week.

A recent series of bluff collapses has brought new attention to the scenic strip of railroad tracks in San Diego County’s smallest city. Shoreline erosion affects most of Southern California, and the tracks in Del Mar are on one of the most vulnerable spots.

Rough plans for rerouting about five miles of track inland and away from the coastal cliffs were recently released by the San Diego Assn. of Governments, or SANDAG, the area’s regional planning agency. Yet that solution would be complicated and costly, and construction is decades away.

Normally, the bluffs erode at a rate of about six inches every year. However, the average can be deceiving, and Mother Nature has picked up the pace this winter.

Two weeks ago, another collapse, recorded on video, took out a 30-foot-long section that went a few feet deep into the rain-saturated cliff. In some spots, the edge of the cliff is just inches from the railroad bed of wood ties and gravel.

Train service was halted for hours until inspectors determined the tracks were safe, a delay that has happened several times after other slides in recent months.

“We didn’t think it would happen as fast as it’s happening now,” said Bruce Smith, a principal engineer at SANDAG.

Smith presented an update on the latest bluff reinforcement project Thursday to the North County Transit District board. The transit district owns the tracks, which are shared by Amtrak, freight trains, and NCTD’s Coaster commuter trains.

Work is scheduled to start in the fall on additional piles and improved drainage structures for the Del Mar stretch of track. Other phases of the work will add more of the same, along with seawalls or other armoring structures to protect the base of the cliffs.

This winter, rains have hastened erosion and landslides in several areas near 10th and 12th streets, where about 200 steel and concrete columns, called soldier piles, have been installed 50 feet deep to hold up the cliffs.

“These particular slides are getting a little close to the piles for comfort,” Smith said.

Stabilization remains the best solution and is far more practical than building a new route, he said. The present plans call for installing more pilings, drainage structures, seawalls and tie-backs, which are walls with anchor cables buried deep into the cliff. Those devices are expected to secure the railroad bed in its present spot through 2050.

“The piles will support the track, it just doesn’t look very nice,” Smith said. “They hold the soil back.”

The coastal rail route is an important part of the regional economy. It carries more than 50 trains a day, and the number is expected to double by 2050.

Thousands of commuters ride the Coaster daily, sparing them the harrowing drive in the congested lanes of Interstate 5. Freight trains mostly move at night, bringing new cars, building supplies and manufacturing materials from the ports at Los Angeles and other points north.

Long-term plans call for moving the tracks off the bluffs by rerouting them as far east as Interstate 5 and in some spots in tunnels as deep as 270 feet beneath the ground. SANDAG’s conceptual plan for five possible alternative routes estimates that construction could cost up to $3.5 billion in today’s dollars.

The high cost of a tunnel route makes it unlikely to happen soon, NCTD executive director Matt Tucker said Thursday. The idea faces numerous environmental challenges. Planning would require extensive public participation and the approval of federal, state and local agencies.

“It appears to be more of a political discussion than a practical discussion” at this point, and for now a better solution is to continue efforts to shore up the tracks in the existing location, Tucker said.

Funding is the key to any railroad improvements, he said, and he encouraged the board members to write or call state and federal officials who can help obtain construction money.

Part of the problem in Del Mar has been that there’s limited space for the tracks, and that space is shrinking.

South of Powerhouse Park, the railroad runs on a line between the bluffs and nearby expensive homes and condominiums. Acquiring any of that private property for additional right-of-way is unlikely.

SANDAG has added a second set of tracks to more than two-thirds of the coastal rail corridor between downtown San Diego and the Orange County border. Eventually, the plan is to double-track the entire route to accommodate the increasing rail traffic, but there is no room for a second set of rails in Del Mar without moving to an alternative location.

Most Del Mar residents want to move the tracks and will continue to push for an alternative route, said Del Mar Councilman Dave Druker, who represents his city on the transit district board.

“Propping up the bluff face is not going to solve anything,” Druker said. “The tracks just don’t belong on the bluffs anymore.”

Residential irrigation at nearby homes and gardens is one of the biggest contributors to erosion, he said. That water constantly soaks through the bluffs and weakens them.

Pedestrian traffic on the tracks also is an issue in Del Mar. There’s only one place to legally cross the rails and get to the beach, at Powerhouse Park. Yet hundreds of people cross illegally elsewhere every day, creating a safety hazard and adding to the erosion of the cliffs.

Originally, the tracks went through the center of Del Mar on Stratford Court and Ocean Avenue. The tracks were moved to the bluffs more than 100 years ago to make room for new homes at what became the center of town.

Phil Diehl writes for the San Diego Union-Tribune.

phil.diehl@sduniontribune.com