Train service between Solana Beach and San Diego will be suspended Saturday and Sunday while a steel-reinforced concrete wall is built to shore up the tracks on the eroding Del Mar bluffs.
The 80-foot-long “shotcrete” structure will be constructed between the exposed concrete piles that have tie-backs already in place, according to transit officials. Tie-backs are anchors drilled into the side of the cliff to hold the 8- to 10-foot-deep piles in place.
The work is the second round of repairs since run-off during heavy rain on Thanksgiving Day eroded the edge of the bluff along the tracks. Two steel plates backed by concrete slurry were installed at the cliff’s edge over the weekend after the holiday.
The concrete wall to be built this weekend is also called “lagging,” a structure that serves the same purpose as the steel plates and coated wood timbers in other places on the bluffs.
North County Transit District, which owns and operates the tracks, has been working with the San Diego Association of Governments and the consultants HNTB Corporation, Leighton Engineering and Mid-Coast Transit Constructors to plan the repairs for the area between Seagrove Park and the end of 15th Street in Del Mar.
Over the weekend Coaster passengers headed south of Solana Beach can board buses for what’s called a “bus bridge” to the Santa Fe depot in downtown San Diego. Regularly scheduled Coaster trains will run between Oceanside and Solana Beach both days. Amtrak’s Pacific Surfliner also will be busing people into San Diego to bypass the construction in Del Mar.
Passengers headed North from San Diego will be bused the entire way to the Oceanside Transit Center. Northbound Coaster passengers who board between Solana Beach and Oceanside will be served by the train’s regular schedule.
Anyone traveling by rail over the weekend should allow extra time to reach their destination, transit officials said. Regular service will resume Monday, though there could be delays of up to 15 minutes that morning.
In January, NCTD and SANDAG are scheduled to begin the fourth of six planned phases of construction that began in 2003 to stabilize the 1.7 miles of bluffs in Del Mar. That work is designed to keep the railroad operating on the bluff through 2050.
Transit officials said last week the emergency repairs will cost up to $5 million and that about $100 million is needed over the next few years for additional construction to stabilize the bluffs in Del Mar.
Studies show the bluffs, which are about 40 feet high in the area being repaired, erode away from the beach at a average rate of about 6 inches annually. However, that erosion usually occurs during a sudden collapse that can peel away a few feet of the cliff at once.
Plans are underway to move the tracks to a different route away from the bluffs, possibly through inland tunnels deep underground. That project will take years of planning and construction, estimated to cost as much as $3.5 billion.
The railroad corridor between downtown San Diego and the Orange County border carries more than 50 trains daily, including freight trains serving the Port of San Diego. Together they carry more than 7 million passengers and $1 billion in goods annually, according to SANDAG.
Train traffic is expected to increase steadily in the decades ahead to serve the area’s growing population and relieve congested roads and freeways.
— Phil Diehl is a reporter for The San Diego Union-Tribune