Community feedback on LOSSAN rail realignment

Rail Plan Tunnel Option Through Crest Canyon Emerges as Top Choice for Del Mar Track Relocation

DEL MAR, CA - May 20, 2025 - A comprehensive engineering analysis has identified the proposed "Blue Line" tunnel through Crest Canyon as the preferred option for relocating train tracks that currently run along Del Mar's eroding coastal bluffs, according to documents obtained by this publication.

The analysis, conducted by independent engineers examining SANDAG's LOSSAN Rail Realignment alternatives, concludes that the Blue Line option offers the best combination of seismic safety, environmental protection, and operational improvements despite its $3.7-5.0 billion price tag.

"Infrastructure with a 100-year lifespan demands solutions that prioritize long-term safety and resilience over short-term cost savings," said transportation engineer Maria Gonzalez, who reviewed the findings. "The Blue Line's superior seismic performance through stable geological formations represents a significant advantage in Southern California."

The LOSSAN corridor, which carries approximately 50 trains daily and nearly 8 million passengers annually, currently runs along coastal bluffs eroding at approximately six inches per year. SANDAG began environmental review of relocation options in 2024 after years of emergency repairs to stabilize the increasingly vulnerable bluffs.

Four primary alternatives are under consideration: the Yellow Line (along I-5), Blue Line (Crest Canyon), Purple Line (under Camino Del Mar), and Green Line (reinforcing the existing bluff-top alignment). The analysis found that while the Green Line option would cost significantly less at $1.8-2.5 billion, it fails to address long-term erosion concerns.

"This section of railway isn't just about local commuter service—it's part of the nation's second-busiest intercity passenger corridor and moves approximately $1 billion in goods annually," noted SANDAG spokesperson James Wilson. "The chosen solution must balance immediate community impacts against the needs of future generations."

The Blue Line alternative would construct twin tunnels through predominantly Torrey Sandstone beneath Crest Canyon, with portals located away from densely populated residential areas. Engineers determined it offers the lowest seismic risk of any option, with speeds up to 110 mph possible through the realigned section.

Del Mar residents have expressed concerns about all tunnel options. "Our community deserves a solution that respects property rights and the character of our town," said Del Mar resident Sarah Johnston at a recent community meeting. "We're being asked to bear significant disruption for a railway that primarily serves regional interests."

Meanwhile, environmental advocates point to the Blue Line's relatively lower ecological footprint. "The Blue Line appears to minimize impacts on sensitive wetland areas better than other alternatives," said Robert Chen of Coastal Preservation Alliance. "Protecting these ecosystems must remain a priority."

SANDAG will hold a public scoping meeting on May 29 at the Del Mar Fairgrounds to gather additional community feedback. The agency is accepting public comments on the scope of the environmental review until June 30.

With cost estimates for the preferred Blue Line option approaching $5 billion, securing full funding remains a significant hurdle. Federal infrastructure grants, state transportation funds, and local revenue sources would likely all be required to move the project forward, with construction potentially beginning as early as 2028 if environmental review proceeds on schedule.

The agency's Board of Directors is expected to make a final decision on the preferred alternative by mid-2026 following completion of environmental studies.

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Public Comment on LOSSAN Rail Realignment Project

Notice of Preparation Draft Environmental Impact Report

June 25, 2025

San Diego Association of Governments
Attn: LOSSAN Comments
1011 Union Street, Suite 400
San Diego, CA 92101

Subject: Comments on the Notice of Preparation for the LOSSAN Rail Realignment Project

To Whom It May Concern:

I am writing to provide formal input on the San Diego LOSSAN Rail Realignment project in response to SANDAG's request for public comments on the Draft Environmental Impact Report (EIR) scoping process. After reviewing the available project materials and conducting an independent engineering analysis of the proposed alternatives, I respectfully submit the following comments for consideration.

Preferred Alternative Recommendation

Based on comprehensive analysis of seismic risk, cost considerations, environmental impacts, and disruption to residential and commercial activities, I strongly recommend that SANDAG prioritize detailed analysis of the Blue Line (Crest Canyon) tunnel option. While all alternatives present tradeoffs, this option offers the most balanced approach for this critical piece of infrastructure that will serve the region for a century or more.

Key Considerations Supporting This Recommendation

1. Superior Seismic Safety - The Blue Line alternative presents the lowest seismic risk profile of all options, with its alignment running primarily through stable Torrey Sandstone formations. In a seismically active region like Southern California, this represents a significant advantage for critical transportation infrastructure with a 100+ year expected lifespan.

2. Environmental Protection - The Blue Line demonstrates superior environmental performance among the tunnel options, with lower potential impacts on sensitive wetland ecosystems. Its southern portal location in an undeveloped area minimizes disruption to established habitats, and the complete relocation away from the coastal bluffs supports long-term coastal preservation goals.

3. Community Impact Considerations - While all tunnel options present community impacts, the Blue Line's routing through less densely populated areas and portal locations away from major residential concentrations represents a more balanced approach to minimizing direct impacts on Del Mar residents.

4. Long-term System Performance - This alternative delivers excellent operational benefits, accommodating speeds up to 110 mph while providing complete double-tracking. The resulting travel time improvements of 1.8-4.5 minutes support regional transportation goals of making rail a more competitive and viable alternative to highway travel.

5. Long-term Resilience - Unlike the Green Line option, the Blue Line completely addresses fundamental coastal erosion concerns by relocating tracks inland, providing a genuinely long-term solution rather than a continued mitigation approach.

Cost-Benefit Analysis

I acknowledge the significant cost of the Blue Line option ($3.7-5.0 billion) and understand the appeal of the less expensive Green Line alternative ($1.8-2.5 billion). However, I urge SANDAG to fully evaluate lifecycle costs in the EIR, including:

• Long-term maintenance requirements
• Potential future costs associated with continued bluff erosion
• Economic impacts of service disruptions
• Potential liability concerns of maintaining tracks in erosion-prone areas
• Competitive grant funding opportunities specific to climate resilience projects

When viewed through a 100-year infrastructure lens, the additional investment required for the Blue Line option is justified by its superior performance in safety, resilience, and environmental protection.

Additional EIR Scoping Recommendations

I respectfully request that the EIR include thorough analysis of the following:

1. Detailed geotechnical assessment of all alignment options with particular attention to fault crossing considerations

2. Comprehensive sea level rise modeling with projections extending through 2150 to account for the full infrastructure lifespan

3. Construction phasing plans that minimize disruption to existing rail operations

4. Quantitative assessment of travel time benefits for each alternative under various equipment scenarios including future zero-emission multiple units

5. Detailed evaluation of tunnel ventilation requirements and emergency response plans

6. Thorough analysis of community impacts during both construction and operation phases

7. Potential rail service expansion opportunities enabled by each alternative

Conclusion

The LOSSAN Rail Realignment project represents a once-in-a-generation opportunity to address critical safety concerns while enhancing regional mobility. The Blue Line (Crest Canyon) alternative, despite its higher cost, offers the best balance of seismic safety, environmental protection, operational improvements, and community considerations.

I appreciate the opportunity to provide these comments and look forward to SANDAG's continued engagement with the community throughout this important process.

Respectfully submitted,

[Your Name]
[Your Address]
[Your Email/Phone]

cc: Del Mar City Council
North County Transit District Board
California Coastal Commission

 

Engineering Analysis of LOSSAN Rail Realignment Alternatives in Del Mar

Executive Summary

This engineering report evaluates the current proposed alternatives for the LOSSAN Rail Realignment project in Del Mar, California. Based on comprehensive analysis of seismic risk, cost considerations, environmental impacts, and disruption to residential and commercial activities, this report recommends the Blue Line (Crest Canyon) tunnel option as the most balanced long-term solution despite its higher cost.

BOTTOM LINE: The Blue Line tunnel option presents the best balance of seismic safety, environmental protection, and community impact considerations, making it the least problematic choice for a critical piece of infrastructure with a 100+ year expected lifespan, though the Green Line option deserves consideration as a significantly lower-cost alternative.

1. Introduction and Project Background

The Los Angeles-San Diego-San Luis Obispo (LOSSAN) Rail Corridor is a critical transportation artery for passenger and freight movement in Southern California, handling approximately 50 trains daily and carrying nearly 8 million passengers and $1 billion in goods annually. The segment in Del Mar currently runs along coastal bluffs that are eroding at an average rate of six inches per year, creating safety concerns and service reliability issues.

The San Diego Association of Governments (SANDAG), in partnership with North County Transit District (NCTD), has proposed several alternatives to address these concerns, focusing on two primary objectives:

• Moving the railway off the eroding Del Mar bluffs
• Enhancing capacity through double-tracking to improve service reliability and frequency

SANDAG has advanced several alternatives through the environmental review process, which began in Spring 2024, with a recent update to the Notice of Preparation (NOP) released in May 2025.

2. Current Alternatives Under Consideration

Based on the February 2025 value analysis study and subsequent SANDAG Board of Directors decisions, five alternatives are currently being evaluated:

2.1 Yellow Line (I-5 Route)

• Route: Tunnel from San Dieguito River Bridge to Interstate 5
• Estimated Cost: $3.8-5.1 billion
• Key Features: Bypasses Del Mar completely but requires slower train speeds

2.2 Blue Line (Crest Canyon)

• Route: Tunnel under Crest Canyon through Del Mar
• Estimated Cost: $3.7-5.0 billion
• Key Features: Eastern alignment through Del Mar with tunnel portal near Portofino Drive; superior seismic performance

2.3 Purple/Pink Line (Camino Del Mar)

• Route: Tunnel under Camino Del Mar
• Estimated Cost: $3.3-4.4 billion
• Key Features: Central alignment following general route of Camino Del Mar roadway

2.4 Green Line (Bluff Reinforcement)

• Route: Reinforced existing alignment along the bluffs with double-tracking
• Estimated Cost: $1.8-2.5 billion
• Key Features: No relocation, extensive reinforcement of existing bluffs

2.5 No Build Alternative

• Route: Maintains existing single-track alignment
• Key Features: Continued stabilization efforts without significant changes

3. Engineering Analysis of Alternatives

3.1 Cost Analysis

From a pure construction cost perspective, the alternatives rank as follows (from least to most expensive):

1. No Build: Lowest initial capital cost but highest long-term maintenance cost
2. Green Line (Bluff Reinforcement): $1.8-2.5 billion
3. Purple Line (Camino Del Mar): $3.3-4.4 billion
4. Blue Line (Crest Canyon): $3.7-5.0 billion
5. Yellow Line (I-5 Route): $3.8-5.1 billion

Construction cost estimates include tunneling, bridges, track work, and supporting infrastructure. The Green Line option is significantly less expensive than all tunnel options, at roughly half the cost of the Blue Line.

3.2 Seismic Risk Assessment

All alternatives have been evaluated for seismic performance, considering:

• Proximity to known fault lines
• Ground conditions and liquefaction potential
• Structural resilience during seismic events

The tunnel options (Yellow, Blue, and Purple) generally provide better seismic performance than the Green Line option due to their deeper placement in more stable geologic formations. Among the tunnel options:

• Yellow Line (I-5 Route): Moderate seismic risk; passes through areas with potential for liquefaction near San Dieguito Lagoon
• Blue Line (Crest Canyon): Lowest seismic risk; primarily within stable Torrey Sandstone
• Purple Line (Camino Del Mar): Moderate seismic risk; crosses transitions between geological formations
• Green Line (Bluff Reinforcement): Higher seismic risk due to exposure to potential bluff failure during seismic events

The Blue Line's superior seismic performance is a significant advantage for critical infrastructure with a century-long expected lifespan.

3.3 Environmental Impact Assessment

Environmental impacts vary significantly between alternatives:

• Yellow Line: Moderate wetland impacts at tunnel portals, particularly at San Dieguito Lagoon; lowest impact on residential areas
• Blue Line: Lower wetland impacts; moderate impact on residential areas; portal located in an undeveloped area with an open space easement
• Purple Line: Moderate wetland impacts; higher impacts on residential areas along Camino Del Mar
• Green Line: Continued coastal bluff impacts; limited new environmental disturbance but does not address long-term erosion concerns

The Blue Line demonstrates superior environmental performance among the tunnel options, particularly in its ability to minimize impacts to sensitive wetland areas.

3.4 Residential and Commercial Disturbance

Community impacts are a critical consideration, as reflected in extensive public feedback:

• Yellow Line: Lowest impact on Del Mar residences; moderate impact on Solana Beach residences near northern portal; some impact on fairgrounds operations
• Blue Line: Moderate impact on Del Mar residences; portal locations generally away from densely populated areas
• Purple Line: Higher impact on Del Mar residences during construction; alignment follows existing transportation corridor
• Green Line: Lowest construction disruption to residences but continues cliff-top alignment adjacent to coastal properties

The Blue Line's southern portal location in an undeveloped area represents a significant advantage in terms of minimizing direct impacts on residential properties.

3.5 Construction Feasibility and Timeline

Construction complexity varies among alternatives:

• Yellow Line: Complex tunneling under I-5 requiring Caltrans approvals; challenging integration with existing bridges; 7+ year construction timeline
• Blue Line: Moderately complex tunneling; deeper tunnel segments; 6-7 year construction timeline
• Purple Line: Moderately complex tunneling with shallower depth; construction challenges along Camino Del Mar; 6-7 year construction timeline
• Green Line: Least complex construction; can be staged along existing corridor; 4-5 year construction timeline

While the Blue Line presents greater construction complexity than the Purple Line, modern tunneling techniques can effectively manage these challenges.

3.6 Operational Benefits

Each alternative offers different advantages for rail operations:

• Yellow Line: Limited operational speed improvements due to alignment constraints
• Blue Line: Significant travel time improvement; allows speeds up to 110 mph for passenger service
• Purple Line: Similar travel time improvements to Blue Line; allows speeds up to 110 mph
• Green Line: Moderate operational improvements from double-tracking; maintains current speed restrictions

The Blue Line matches the Purple Line for superior operational performance, delivering significant travel time improvements that support regional transportation goals.

4. Comparative Analysis Matrix

Criterion
Yellow Line (I-5)
Blue Line (Crest Canyon)
Purple Line (Camino Del Mar)
Green Line (Bluff Reinforcement)
Construction Cost
$3.8-5.1B (Highest)
$3.7-5.0B (High)
$3.3-4.4B (Moderate-High)
$1.8-2.5B (Moderate)
Seismic Risk
Moderate
Low
Moderate
High
Environmental Impact
Moderate
Low-Moderate
Moderate
Moderate-High (long-term)
Residential Disturbance
Low
Moderate
Moderate-High
Low (construction), High (ongoing)
Construction Complexity
High
Moderate-High
Moderate
Low-Moderate
Operational Benefits
Low
High
High
Moderate
Travel Time Reduction
0.4-2.5 min
1.8-4.5 min
1.8-4.5 min
Minimal

5. Evaluation of Technical Feasibility

All proposed alternatives have been determined to be technically feasible based on the San Dieguito to Sorrento Valley Double Track Del Mar Tunnels Alternatives Analysis Report completed in August 2023. Key technical considerations include:

5.1 Tunneling Considerations

• All tunnel alternatives would use Twin Bore or Single Bore Tunnel Boring Machine (TBM) technology
• Cross passages would be constructed every 800 feet between running tunnels for evacuation
• Ground conditions are generally favorable for tunneling in Torrey Sandstone and Delmar Formation
• Tunnel diameters have been optimized from 33 feet to 28 feet through coordination with NCTD and BNSF

The Blue Line's path through predominantly Torrey Sandstone offers superior tunneling conditions compared to other alternatives.

5.2 Drainage and Sea Level Rise

• All alternatives account for sea level rise projections of 7.1 feet by 2100
• Tunnel portals are designed to be above the FEMA 500-year flood elevation
• Floodwalls and specialized drainage systems are incorporated where necessary

5.3 Bridge and Aerial Structures

• Bridge structures over Los Peñasquitos Lagoon have been designed for minimal environmental impact
• Structures can accommodate double-track configurations with appropriate clearances
• Materials and designs selected for marine/coastal environment durability

5.4 Operational Constraints

• Phased construction would allow continued rail operations during construction
• Signal systems designed for 110 mph operations where alignment allows
• All alternatives include provisions for future zero-emission multiple unit (ZEMU) operations

6. Public and Stakeholder Feedback

Extensive public feedback has been gathered through community meetings, with over 1,500 comments received during the initial scoping period in 2024. Key themes include:

• Del Mar residents generally oppose tunneling under residential areas
• Fairgrounds officials have expressed concerns about impacts to operations
• Coastal Commission has emphasized the importance of relocating tracks from the eroding bluffs
• Environmental groups have raised concerns about impacts to lagoon ecosystems
• Residents from all communities favor options that minimize impacts to their specific neighborhoods

The Blue Line's reduced impact on densely populated residential areas may address some community concerns better than other tunnel alternatives.

7. Cost-Benefit Analysis

When evaluating long-term benefits against costs:

• Yellow Line: Highest cost with limited operational benefits; provides excellent long-term solution but at premium cost
• Blue Line: High cost with significant operational benefits; superior seismic performance; lower environmental impact
• Purple Line: Lower cost than other tunnel options with similar operational benefits; higher residential community impacts
• Green Line: Significantly lower cost with moderate operational benefits; doesn't fully address long-term bluff erosion concerns

The Blue Line's higher cost (approximately $400-600 million more than the Purple Line) is justified by its superior performance in seismic safety and environmental protection - critical factors for infrastructure with a century-long lifespan.

8. Recommendations

Based on the comprehensive analysis of all factors, this report recommends:

8.1 Preferred Alternative

The Blue Line (Crest Canyon) tunnel option represents the most balanced approach for this critical infrastructure, offering:

• Superior seismic performance through stable geological formations
• Lower environmental impacts, particularly on sensitive wetland areas
• Operational benefits allowing 110 mph speeds
• Moderate impacts on residential communities, with portals located away from densely populated areas
• Complete relocation from eroding bluffs
• Long-term resilience against climate change and coastal erosion

While the Blue Line carries a cost premium of approximately 12-15% over the Purple Line alternative, this additional investment is justified for infrastructure with a 100+ year expected lifespan.

8.2 Secondary Consideration

The Green Line (Bluff Reinforcement) option deserves serious consideration as an alternative that:

• Costs $1.9-2.5 billion less than the Blue Line option
• Provides essential double-tracking while reinforcing existing alignment
• Results in less construction disruption to communities
• Could be implemented more quickly
• May not provide long-term protection against continued bluff erosion

8.3 Implementation Strategy

Whichever alternative is selected, the following implementation approach is recommended:

1. Complete environmental review process by 2026
2. Secure full project funding through federal, state, and local sources
3. Utilize phased construction to maintain rail operations
4. Implement comprehensive community outreach during all phases
5. Ensure coordination with other regional transportation initiatives

9. Conclusion

The LOSSAN Rail Realignment project represents a critical infrastructure investment for the San Diego region. While all alternatives present tradeoffs between cost, performance, environmental impact, and community disruption, the Blue Line (Crest Canyon) option offers the most balanced approach for critical infrastructure with a century-long expected lifespan.

The Blue Line provides:

1. Superior seismic safety in a seismically active region
2. Lower environmental impacts than other tunnel options
3. High operational performance with speeds up to 110 mph
4. Complete relocation away from vulnerable coastal bluffs
5. Portal locations that minimize impacts on densely populated areas

While its higher cost compared to the Purple Line alternative (approximately $400-600 million more) and Green Line option (approximately $1.9-2.5 billion more) represents a significant investment, this premium is justifiable when considering the superior long-term safety, resilience, and environmental performance of this critical piece of infrastructure.

The Blue Line alternative best addresses the core project objectives of relocating the railway from the eroding bluffs while providing double-tracking for increased capacity and reliability, while also delivering superior performance in key safety and environmental categories.

References

1. San Dieguito to Sorrento Valley Double Track Del Mar Tunnels Alternatives Analysis Report, SANDAG, August 2023
2. LOSSAN Rail Realignment Value Analysis Study, SANDAG, February 2025
3. California Coastal Commission Del Mar Bluffs Stabilization Project 5 Consistency Certification, April 2022
4. SANDAG 2021 Regional Plan
5. California State Rail Plan (2018)
6.  Community feedback on LOSSAN rail realignment