LOSSAN Rail Realignment

In 2007, Caltrans and the Federal Railroad Administration (FRA) released the final LOSSAN Corridor Program Environmental Impact Report/Statement (EIR/EIS) evaluating conventional rail improvements for the corridor. Due to the high pedestrian activity in the City of Del Mar, and especially along the coast, the report recommended relocating the rail corridor away from the fragile Del Mar bluffs into an underground tunnel. This will achieve complete grade separation, significantly improving safety for pedestrians, bicyclists, and vehicles. The EIR/EIS identified two possible alignment options: a tunnel under Camino Del Mar or a tunnel under I-5.

In 2017, SANDAG completed a conceptual alignment study to discover ways to improve speed, capacity, and safety of future rail service. It identified five possible alignments, including the two tunnel options recommended by the 2007 study. The other three options were Crest Canyon, Crest Canyon Higher Speed, and I-5 East.

In response to threats from erosion and climate change, SANDAG and partner agencies commissioned the San Diego Regional Rail Corridor Alternative Alignment and Improvements Conceptual Engineering Study for the San Diego section of the LOSSAN Corridor in summer 2020. Partners included the North County Transit District (NCTD), the California Department of Transportation (Caltrans), and the United States Department of Transportation (US DOT).

In March 2021, we studied existing rail line conditions, analyzed proposed alignments, and conducted exploratory geotechnical work. To understand challenges and opportunities, we met with key cities, agency partners, and environmental organizations.

We refined the five potential alignments identified in the 2017 study in the San Dieguito to Sorrento Valley Double Track Alternatives Analysis Report. The refined alignments were Camino Del Mar, Crest Canyon Higher Speed, Crest Canyon Above, Crest Canyon Below, and I-5.

In 2022, Senate President Pro Tem Toni Atkins secured $300 million in the state budget to move the study forward to the environmental clearance and final design phases. This was a huge step forward for this critically important regional project.

In summer and fall 2023, we hosted community open houses and public information sessions to obtain feedback on the most feasible rail alignment options. Through these efforts, we had more than 300 points of contact, including 200+ written comments, 100+ emails, 30+ public comments, 35+ drawn alignment suggestions, and 25 meetings through our virtual and in person field offices.

In June 2024, we released a Notice of Preparation (NOP) of a Draft Environmental Impact Report (EIR). In response to the comments received on the NOP, we conducted a value analysis study to improve the existing alignment alternatives and identify new ones for consideration.

Based on comments received on the NOP and the results of the value analysis study, we recommended four alignments be included for analysis in the Draft EIR. The SANDAG Board approved the analysis of the four alignments, and we will advance the design of these alternatives for inclusion in the Draft EIR. 

An updated NOP was posted in May 2025 for a 45-day public comment period. Technical studies will start in the summer to support the preparation of a Draft EIR that will be circulated for public review.

The Board of Directors approved the analysis of four alignments, including the no build option. A decision has not been made on which proposed alignment will be built. All practical alternatives are still being considered and will be studied during the formal environmental review process under CEQA and NEPA.

Yes, the Del Mar Bluffs Double Track Reinforced alternative concept would maintain the location of the existing rail alignment on the bluffs and add a second at-grade track to the east within the railroad right-of-way.

Under CEQA and NEPA guidelines, SANDAG must also study a “No Project Alternative” which would include the continuation of major stabilization efforts that would be required to protect the single-track alignment.

Due to the topography of the existing terrain, it would likely be challenging or impossible to accommodate the 2% maximum slope design requirement with an entirely at-grade or above-grade option. For this reason, three of the proposed alternative alignments include a tunnel as part of the design.

During the environmental phase, we will study the potential impact of construction and train traffic on residents. Experts will evaluate noise and vibration reduction methods that will work best in this specific situation. Our goal is to deliver a solution that minimizes vibration and noise.

The depth will vary depending on the topography above the tunnel. In many areas, the tunnel would be more than 300 feet below the surface. At this level of design, the general rule of thumb is that there should be cover of at least the diameter of the tunnel above the bored tunnel. For example, if the tunnel diameter is 30 feet, the minimum depth would be 30 feet from the existing ground surface to the top of the tunnel.

We conducted preliminary geotechnical studies, and results can be found in Appendix E of the Alternatives Analysis. More detailed geotechnical studies will be conducted, and the results will be included in the Draft Environmental Impact Report.

A value analysis is a technical study in which we revisited the alternatives originally proposed in the NOP that was released in June 2024, and identified new ones for consideration. SANDAG invited representatives from the cities of Carlsbad, Del Mar, Encinitas, Oceanside, San Diego, and Solana Beach, as well as representatives from the 22nd District Agricultural Association, Metropolitan Transit System, North County Transit District, and Caltrans to participate in the study. 

Read the Value Analysis Study Report for more details. 

Topics for environmental study under CEQA include:

• Aesthetics
• Air quality
• Biological resources
• Cultural resources
• Energy
• Geology and soils
• Greenhouse gas emissions
• Hazards and hazardous materials
• Hydrology and water quality
• Land use and planning
• Mineral resources
• Noise and vibration
• Population and housing
• Public services
• Recreation
• Transportation
• Tribal cultural resources
• Utilities and service systems
• Wildfire
• Mandatory findings of significance

Yes, SANDAG is working closely with the Orange County Transportation Authority (OCTA) and is a key stakeholder in their Coastal Resiliency Working Group. Together, we are evaluating strategies to protect the railroad corridor and maintain rail operations while developing a long-term vision. Additionally, both SANDAG and OCTA are members of the LOSSAN agency, where we collaborate to improve passenger rail ridership, revenue, on-time performance, operational flexibility, and safety.

Yes, SANDAG will follow the latest guidance from the California Ocean Protection Council to ensure the project meets 100-year sea level rise estimates.

Yes, rail operations will continue during the construction phase.

Yes, our goal is to maintain safe access to local businesses during business hours, to the extent possible.

Yes, access for emergency services will be maintained during construction.

Preliminary engineering and environmental studies will need to be completed to identify the full range of benefits. At a minimum, the project will protect the rail line from landslides, erosion, and seismic activity along the Del Mar bluffs and secure the long-term reliability of transit service through our region. We also expect the realignment to facilitate coastal access and create new recreation and building opportunities.

The realignment project is part of a larger program of improvements on the LOSSAN Corridor. It is still too early to know what property interests might be required. To learn more about this process, please visit our Real Estate and LOSSAN Rail Realignment page.

SANDAG presented preliminary results of the planning study to several community planning groups, the Del Mar City Council, and other technical boards between 2020 and 2023. Feedback from public meetings has influenced the alternatives evaluated in the study. More than 1,500 public comments were received during the initial public scoping period in 2024. The comments were reviewed by the project team and will be used to help guide the next phase of the environmental process. The latest work is only the beginning of a lengthy community-oriented process. SANDAG intends to maximize public input opportunities throughout the project.