Innovative Project Delivery in a Sensitive Coastal Habitat

The San Elijo Double Track Project is a $78.6 million project that added 1.5 miles of new rail near Encinitas, California. It replaced the old wooden trestle bridge with a modern longer reinforced concrete bridge, constructed a new pedestrian undercrossing and provided signal and grade crossing improvements at Chesterfield Drive. The new double track bridge pile spacing at the lagoon inlet allows for increased tidal flows and creates a more natural environment in the lagoon while the addition of  double track through the lagoon eliminates the single track bottleneck in rail operations and provides a continuous 4.2 miles stretch of Double Track.

We served as the lead designer for track, structures, drainage, hydrology and hydraulics, utilities, real estate and right-of-way services, and environmental services.

The project used a first-of-its-kind delivery method and innovative methods to overcome a challenging project site while protecting sensitive coastal habitat. It now provides a safer, more reliable and environmentally friendly transit option for the future. And it has been welcomed by the community.

“It is exciting to see this long-awaited project come to fruition because it is an important step towards making regional transportation more accessible,” said Encinitas Mayor Catherine Blakespear.

An Important Site for Passengers, Pedestrians, Wildlife — and Southern California

Built nearly 80 years ago, the wooden trestle bridge spanning the opening of the San Elijo Lagoon was used by up to 70 trains per day. The corridor is instrumental to Southern California’s economic vitality — it is part of the second-busiest intercity passenger rail line in the United States and is the only viable freight rail link between San Diego and the rest of the country.

The team designing the new bridge was tasked with making improvements in several key areas. The bridge’s 100-year lifespan and prestressed, precast construction was designed to accommodate future sea-level rise. A new pedestrian underpass was designed in the middle of the lagoon to provide coastal access to the Solana Beach community. At the northern end of the project, a new Class 1 bike trail parallels the tracks providing walkable spaces for the Cardiff-by-the-Sea community. It connects to a state of the art grade crossing at Chesterfield Drive, allowing pedestrians, cyclists and vehicles to safely cross a complex intersection. 

This project was the California Department of Transportation’s District 11 and SANDAG's first construction manager/general contractor delivered project. This method allowed multiple projects in the vicinity — including the Interstate 5 San Elijo Highway Bridge Widening and San Elijo Lagoon Environmental Restoration Project — to be constructed concurrently, saving time and money while minimizing impacts to the lagoon. By integrating all environmental mitigations into a single project, Caltrans saved millions of construction dollars and avoided schedule delays.

Diverse Goals, Successful Outcomes

Beyond simply adding new rail, the team had a diverse set of goals to meet. The project opened to the public on time, and the team accomplished:

• Improved flow to the lagoon with a new rail bridge that was longer and had fewer piles.
• Improved multi-modal access at the Chesterfield Drive at-grade crossing allowing for vehicles, pedestrians and cyclists to negotiate the intersection safely. This also connected to a new Class 1 bike trail that was designed and constructed concurrently with the rail project.
• Provided mid-lagoon pedestrian undercrossing to connect to future Harbaugh and San Elijo Lagoon Trails and coastal access to the City of Solana Beach community.
• Provided improvements necessary for the City of Encinitas to institute a quiet zone; which also installed supplemental safety measures.
• Supported a regular formal partnering program, which resulted in the successful implementation of the Project First Approach between Caltrans, SANDAG, NCTD, contractor and HDR.
• Minimized disturbance in the San Elijo Lagoon through an environmental mitigation program.