Five routes proposed for Del Mar train tunnel as reinforcement of eroding bluffs continues
Five possible routes for moving the train tracks off the eroding Del Mar bluffs were outlined this week by regional transportation officials.
Four of the ideas involve twin sets of tracks drilled or bored through the ground as deep as 270 feet beneath the surface and up to a mile or more inland. The fifth alternative is a deep trench that follows Camino Del Mar, also known as Highway 101, below the roadway through the center of town.
“They are all costly alternatives,” said Linda Culp, a principal planner for the San Diego Association of Governments (SANDAG), which is leading the project.
Construction is expected to cost between $2.5 billion and $3.5 billion, Culp said at a Del Mar City Council meeting Monday, Feb. 11. The money would come from a combination of federal, state, regional and local sources.
Completing the project could take decades.
However, rerouting the tracks at Del Mar is essential. Erosion eats away constantly at the limited railroad right-of-way on the seaside bluffs.
So far, the track bed remains stable, though there have been several bluff landslides so far this winter, said Bruce Smith, a principal engineer at SANDAG.
The existing route has been reinforced multiple times over the years with stopgap measures such as pilings and walls.
Planning is complete and permits are being obtained for another $3 million bluff stabilization project that could start later this year, Smith said. New pilings will be drilled deep into the sandy soil, and the existing drainage structures for rainwater and irrigation runoff will be repaired
More work costing an additional $70 million to $90 million will be needed over the next 30 years “to keep the bluffs in a condition to run trains on,” Smith said. That also will involve building sea walls, pilings, tie-back structures and more.
Meanwhile, North County Transit District, which owns the tracks and operates the Coaster commuter trains, wants to keep people off the tracks by erecting a fence. The frequent pedestrian traffic hastens erosion.
But the idea of a fence doesn’t sit well in Del Mar, where hundreds of people cross the tracks illegally every day to surf, swim or just enjoy the ocean view. Many of them have lived there 30 years or longer and consider beach access, across the tracks, a basic right.
Rerouting the tracks would eliminate the trespassing problem, which is also a public safety hazard. About a dozen pedestrians are killed annually on the tracks between San Diego and Oceanside, many by suicide, a danger that’s virtually eliminated by placing the tracks underground.
As it is, the single set of tracks at Del Mar is becoming a choke point on the vital coastal rail route.
A second set of tracks has already been built for about two-thirds of the route from San Diego to Orange County, and more double-tracking is planned. Del Mar is one of the last segments with a single set of tracks, primarily because of the many difficulties of choosing and building a new route.
The railroad now carries about 50 trains a day, and rail traffic is expected to double by 2050, Culp said.
One of the first and probably most time-consuming hurdles to leap before construction will be choosing the new route. The process will involve numerous public agencies, environmental studies and extensive public input.
All five of the proposed alternatives would reroute about five miles of the track, Culp said.
The Camino Del Mar route would probably be the least expensive, in part because it will not need property now occupied by homes or commercial buildings. Even so, construction, using a style called “cut and cover,” would last two years or longer and would disrupt traffic and other activities along the route during that time.
That route would require digging a trench 10 to 70 feet deep beneath Camino Del Mar. During construction, the trench would be topped with steel plates to allow vehicular traffic to continue during the work.
The tunnel portion would be 10,200 feet long on the Camino Del Mar route, and 11,600 feet to 13,400 feet long on the other routes. All of the bored tunnels would require an emergency-access portal to the surface about every 2,500 feet.
The two Crest Canyon routes are the shortest and fastest for traveling trains, Culp said. Alternative No. 2 is the shortest total length, at 4.8 miles, and would include the deepest of the tunnels, at 270 feet, but would allow passenger trains to travel the fastest, up to 90 mph through the passage.
Alternative No. 3 through Crest Canyon is slightly longer and a bit more elevated, with a depth of 250 feet, but the benefit would be fewer properties would need to be acquired, Culp said.
Alternatives Nos. 4 and 5 both take the tracks out to the Interstate 5 right-of-way. Those are both the longest and most costly alignments, so they are slower for trains, but they would require less private property to be acquired. There the tracks would only need to be up to 120 feet deep.
Each of the four twin-bored tunnels would include a third, smaller tunnel, about 10 feet in diameter, between the two for emergency access. The Camino Del Mar route would have emergency access from stairs.
Del Mar city officials have long supported the effort to reroute the tracks.
In addition to the public safety benefit, some people said, rerouting and double-tracking the railway would bring economic benefits to the entire region, primarily from the increase in freight traffic. That could be an argument for building it sooner.
“People want to know if we’ll ever get a tunnel,” Councilman Dwight Worden said Monday.
The cost may seem like a lot, Worden said, but the region has other infrastructure projects underway that cost similar amounts. The Mid-Coast Trolley project in San Diego, for example, is expected to cost more than $2 billion.
He suggested the community could help speed up the project by getting involved in the effort to choose a preferred route. Once the project is “shovel ready,” with permits and approvals in hand, it is more likely to get grant money for construction.
“It’s just a big, complicated task,” Warden said.
-- Phil Diehl is a reporter for The San Diego Union-Tribune
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