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Little By Little, San Diego’s Coastal Rail Line Double Tracked

Photo by Kris Arciaga

The existing single track rail line across the San Elijo lagoon

Commuters who ride the train along the San Diego coastline are less likely to be bothered than car commuters by the major construction launching this month on the North Coast Corridor project.

Rather than closing lanes, the major work to be done on the rail line involves building a new concrete bridge across the San Elijo lagoon next to the existing train trestle bridge.

The new rail bridge is expected to open in 2018. It will be wide enough for two railway tracks built side by side, so trains can pass each other. Double tracking speeds things up for train passengers, said Jim Linthicum, mobility director at the San Diego Association of Governments, or SANDAG, San Diego’s regional planning agency.

“You notice every once in a while, not at the station, the train will just stop. That’s because it’s in a double track area and it’s waiting for another train to get out of a single track area. And so the more double track you have, it eliminates the need for that train to sit … it just keeps on going.“

Photo credit: SANDAG

The new rail bridge that will start construction over the San Elijo lagoon is due to be completed in 2018

The North Coast Corridor project launching this month adds only a little more than two miles of rail double tracking, while it adds 14 miles of extra car pool lanes to the freeway. Plus, only about half of the 60-mile rail line is double tracked. But Linthicum said train tracks and roads function differently: stretches of single-track rail line don’t create bottlenecks the same way narrower roads do.

“If you were to reduce southbound (Interstate 5) from four lanes to three for even 100 yards, you would create a huge bottleneck,” he said. “But it doesn’t work that way on the rail. As there’s more and more trains, the trains need a place to pass each other. The more double track you have, the more flexibility you have, because your trains can pass anywhere.”

Linlithcum said replacing a single rail track with a double track, even for short sections, means more trains can be added to the line.

The line crosses six environmentally sensitive coastal lagoons. The rail bridge over the Agua Hedionda lagoon already has two tracks and much of the line from Oceanside to the Batiquitos lagoon has already been double tracked. The new bridge over the San Elijo lagoon will create another four-mile stretch along the coast. Its concrete columns will be more widely spaced, reducing the effects on the lagoon's tidal flow.

Photo credit: sandag

Projected increase in trains along the North Coast Corridor, 2012

About 50 trains currently travel down the coastal rail line every weekday, including the Coaster, the Amtrak Surfliner and BNSF freight trains. Double tracking is projected to allow that number to double by 2030: SANDAG projects Coaster trains will increase from 22 to 54 a day by 2030.

The North County Transit District, which operates the Coaster, did not respond to queries about current ridership, but according to the the website, 5,700 people a day ride the Coaster.

Linthicum said the plan is to double track 99 percent of the coastal rail line within 40 years, when funding becomes available. Sections near Del Mar and up near the Orange County line are the most environmentally challenging.


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