Most conversations about the Del Mar bluffs end with the trains. This one starts there.
SANDAG’s updated Notice of Preparation for the San Diego LOSSAN Rail Realignment Project, released in May 2025, lays out what its environmental impact report will study. Reading it closely, a homeowner learns two things. No alignment has been chosen. And every option on the table involves heavy construction somewhere in or near Del Mar.
What follows is a reading of that document from the point of view of a house, not a train. It is not a forecast. Studies change, and decisions belong to the agencies.
The problem the study is trying to solve
The notice is plain about the bluffs. It estimates average bluff retreat at 0.4 to 0.6 foot per year, and notes that large episodic failures can take more than 20 feet of bluff edge in a single event. The current stabilization phase was designed with a 30-year life, but the notice describes stabilization and emergency repairs as something less than a long-term answer to sea level rise and erosion.
The Coastal Commission, the notice adds, has required SANDAG to evaluate removing stabilization infrastructure before its approvals expire. That condition is part of why relocation is being studied at all.
Four alignments and a baseline
The draft environmental report will study four build alternatives and a No Project alternative.
Three tunnel options. Each would use a north portal, a bored tunnel and a south portal, with double track:
- San Dieguito Bridge to I-5. A bridge along the south side of San Dieguito Lagoon, over Jimmy Durante Boulevard and Racetrack View Drive, into a portal near Racetrack View Drive, then under the I-5 corridor to a portal on a knoll near I-5. The notice says a more northerly variation raised by stakeholders will also be explored.
- Under Crest Canyon. About 5.1 miles, entering a portal under Jimmy Durante Boulevard and following under Crest Canyon to the knoll portal near I-5.
- Under Camino Del Mar. About 4.9 miles, from the Jimmy Durante portal mostly under Camino Del Mar to a portal near Carmel Valley Road and North Torrey Pines Road, then on a bridge over Los Peñasquitos Lagoon.
One non-tunnel option. The Del Mar Bluffs Double Track Reinforced alternative would keep the rail on the bluffs, add a second track, drop the line into a trench with retaining walls, pass under a raised Coast Boulevard, and add roughly 1.5 miles of seawalls up to about 20 feet high.
No Project. The single track stays on the bluffs, with continued and possibly expanded stabilization.
Reading each option from a house
Each alternative touches private property differently. A few passages stand out.
The notice says the portal under Jimmy Durante Boulevard would raise that road, and that portal structures “would potentially extend into commercial and residential properties.” For owners near that intersection, that line deserves attention.
The value analysis summarized in the notice recorded interest in alignments that minimize effects on private property, “including subsurface easements.” A bored tunnel under a neighborhood raises questions an owner may not have considered: what lies beneath the lot, at what depth, and under what legal arrangement.
The bluff-top alternative keeps the work on the rail corridor, but at a larger scale. Longer and taller seawalls, a trench and a raised road are significant construction close to homes on the North and South Bluffs.
Even No Project is not quiet. It means continued stabilization work for as long as the tracks stay on the bluffs.
What the environmental report will weigh
The notice lists twenty resource categories the report will address. For homeowners, a few carry the most structural interest:
- Geology and soils. How each option interacts with the bluffs, canyons and lagoon edges.
- Noise and vibration. Tunneling, pile work and trenching all produce vibration. How it is measured and limited matters for older homes and fragile finishes.
- Hydrology and water quality. Portals, trenches and lagoon crossings change how water moves.
- Land use, population and housing. Where right-of-way or easements might be needed.
Construction components common to the tunnel options include utility relocation, drainage and roadway changes, removal of prior bluff stabilization, and possible placement of beach-quality sand from tunneling on nearby beaches.
A record that predates any decision
Whatever is chosen, construction is a long way off. That is an argument for doing one modest thing now: documenting the condition of your home while it is unaffected.
A baseline record usually includes:
- Dated photographs of every existing crack, inside and out, with a scale in frame.
- Floor-level readings, if you have or can obtain them.
- The condition of retaining walls, garden walls, and the foundation edge.
- Notes on doors and windows that bind, and when.
- Copies of any soils, geotechnical or as-built records for the lot.
Our post on documenting a Del Mar home covers method in more detail. If you live near Crest Canyon, the canyon-edge post describes the ground there.
Keeping perspective
This study does not change what matters on your own lot today. The Del Mar annex to the County hazard plan maps coastal bluff erosion on the North and South Bluffs and inland bluff erosion on the North and South Hills. Drainage, irrigation and leaks on private property remain the factors an owner controls.
It is also worth separating the rail corridor from private bluff-top lots. Public stabilization protects the tracks; it is not a review of neighboring homes, and the City’s own bluff rules for private development continue to apply whichever alignment moves forward. An owner who keeps roof water off the bluff edge and fixes leaks promptly is doing the most useful work available, regardless of what happens on the railroad right-of-way.
What the study adds is a reason to watch. Draft documents, comment periods and design refinements will each say more about where work would occur. Reading them as they appear is the measured approach.
How we can help, quietly
We do not take positions on the alignment, and we make no prediction about outcomes. What we offer is a careful baseline evaluation of a home’s foundation and structure, written so it can be compared later. Where questions run to geology or design, we coordinate with licensed engineers as needed.
Our pages on bluff and hillside homes and bluff and seawall stabilization describe that work. We serve all of Del Mar. To arrange a baseline visit, request a Free Quote.