LOSSAN Rail Realignment

In 2007, Caltrans and the FRA released the final LOSSAN Corridor Program 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 U.S. 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 an NOP of an 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. 

Technical studies began in September 2025 to support the preparation of a Draft EIR and a Draft EIS. The draft document(s) will be circulated for public review when they are completed. 

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 the California Environmental Quality Act (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 materials transported on the rail line today are the same materials that will be transported on the rail line in the future, whether a tunnel or surface line is chosen. Military cargo includes Department of Defense equipment, consisting mostly of wheeled and tracked vehicles loaded on flatcars. Bulk ammunition is not shipped by rail on the LOSSAN Corridor (see the letter from the Department of Defense). According to BNSF, grain, raw materials, finished electronics, clothing, consumer goods, and low-sulfur coal are among the products shipped by rail. Read the BNSF FAQs for more information.

Hazards and hazardous materials is one of the resource areas that will be studied in the Draft EIR. Any materials that have the potential to harm the environment or human health in any way will be analyzed.

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 EIR and Draft EIS.

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 (MTS), NCTD, and Caltrans to participate in the study. 

Read the Value Analysis Study Report for more details. 

Proposed topics for environmental study include:

• Aesthetics 
• Air quality 
• Biological resources 
• Coastal zones 
• Cultural resources 
• Energy 
• Geology and soils 
• Greenhouse gas emissions 
• Hazards and hazardous materials/waste 
• Hydrology, water quality, and floodplains 
• Land use and planning 
• Listed species 
• Noise and vibration 
• Paleontological resources 
• Population and housing 
• Public safety 
• Public services 
• Parks and recreational facilities 
• Transportation 
• Tribal cultural resources 
• Utilities and service systems 
• Waters of the U.S. 
• Wildfire 

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.

Under CEQA, SANDAG must evaluate the potential environmental impacts of its projects, consider alternatives, and identify mitigation measures to reduce significant and unavoidable impacts. At the federal level, the NEPA requires similar reviews, ensuring that federally funded or approved projects fully disclose their environmental consequences. Together, CEQA and NEPA provide transparency, promote public engagement, and lead to responsible decision making. Read more on the Environmental Compliance page.  

The purpose of a scoping meeting is to introduce the approach for the preparation of an EIR and/or EIS and ask for input on the environmental issues to be addressed and the alternatives to be explored.

The purpose of an NOP and an NOI is to solicit input from agencies, organizations, and the public on the scope and content of the environmental information to be included in the Draft EIR and Draft EIS, respectively.

Comments received during the scoping period are part of the project’s administrative record and will inform the development of the Draft EIR and Draft EIS.

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.

SANDAG is still in the early stages of an environmental study to evaluate routes and improvements for the LOSSAN Corridor. A decision has not been made on which proposed alignment will be built. It is too soon to know how many homes will be impacted, and SANDAG has not reported any numbers. The Draft EIR and Draft EIS will identify potential property impacts for each of the alternatives. Visit the Real Estate and LOSSAN Rail Realignment page to learn more.

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. Thousands of public comments were received during the public scoping periods in 2024 and 2025. 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.