The single-track wooden trestle that has carried trains across Batiquitos Lagoon since the 1940s is close to retirement. SANDAG and Caltrans built a concrete double-track bridge beside it. Their stated goal is to move train traffic onto that new bridge "in late 2026," then pull the old track, replace the erosion protection and demolish the trestle. The heaviest work at the lagoon is happening this fall because of a small endangered seabird that is no longer here. The same calendar brings the lagoon's winter birds in while the crews are working. If you walk the north shore trail between now and spring, you will see both.
A Bird Sets the Construction Calendar
The Batiquitos Lagoon Double Track project covers 0.6 miles, from La Costa Avenue in Encinitas to just north of Avenida Encinas in Carlsbad. Its estimated cost is $166 million, funded by TransNet and state Solutions for Congested Corridors grants. Construction started in August 2024 and is expected to finish in 2028. SANDAG builds in one fixed condition: all construction stops from April 15 to July 31 each year, during California least tern nesting season.
That leaves the project eight and a half working months a year, and the clock restarts every August. KPBS reported on August 11 that crews were going back into the lagoon because "most of the endangered terns have migrated for the winter." The terns nest in dense colonies near the lagoon mouth at South Ponto Beach. The San Diego Union-Tribune reported that after breeding, they spend the winter in Mexico.
The project has also supplied material for the tern's nesting habitat. After the 2025 nesting season, KPBS reported that SANDAG used sand from the rail work to rebuild an eroding nesting site. Crews also added crushed oyster shells, and roofing tiles and mesh chick barriers were planned. Project planners told the Union-Tribune that about 8,000 cubic yards of construction sand went onto the nesting site. More beach-quality sand is planned for nearby beaches through 2028. SANDAG's project map also shows proposed grading for tern habitat just south of the bridge work, on the west side.
What's Happening on the Water Right Now
Since August, the work has centered on track construction between La Costa Avenue and Avenida Encinas. Most of it runs Monday through Friday, 7 a.m. to 5 p.m. Some weekend work is planned, and intermittent night work may be required when rail service is temporarily shut down. In its August 13 City Manager's Update, the City of Carlsbad told people nearby to expect "some noise, dust, lane closures and increased train horn activity."
The latest posted work was overnight. From about 11 p.m. Saturday, October 10, to 5 a.m. Sunday, October 11, crews worked just south of the La Costa Avenue overcrossing on rail destressing. SANDAG calls this "a critical operation for trackwork installation." It sets the rail so it can expand and contract with temperature changes. Crews destress rail when new track is getting close to carrying trains. As of today, SANDAG has not announced a date for moving trains onto the new bridge, and none of the official updates says it has happened. The public target is still "late 2026."
Here are the dates that matter between now and the next nesting pause, from SANDAG's project page, NCTD's service alerts and Pacific Surfliner's travel advisories:
| Date | What's scheduled | Status |
|---|---|---|
| Oct. 10–11, 2026 | Overnight rail destressing south of La Costa Avenue; no Pacific Surfliner service San Diego to San Luis Obispo | Passed |
| Nov. 7–8, 2026 | NCTD work window shared by the Batiquitos project, Del Mar Bluffs Phase 5 and another double-track project; no Surfliner service on the corridor, no bus bridge | Posted |
| Late 2026 | Trains move to the new double-track bridge | Target, no date announced |
| Jan. 9–10, Jan. 23–24, Feb. 20–21, Mar. 6–7, 2027 | NCTD work windows assigned to the Batiquitos project alone | Proposed |
| Apr. 15–Jul. 31, 2027 | Annual least tern pause | Fixed |
| 2028 | Project completion | Projected |
NCTD labels its 2026–2027 list "Proposed Absolute Work Windows." Pacific Surfliner treats the November 7–8 closure as corridor-wide. That weekend covers more than the lagoon, and SANDAG has not said it is the cutover. Starting in January 2027, the Batiquitos project is the only project assigned to the work windows. Those are the last scheduled windows before the terns return. SANDAG has not said whether the trestle demolition has to be finished before that April pause.
The Same Months Bring the Winter Birds
Construction season and the lagoon's winter bird season both start once the terns have left. The lagoon is a protected 610-acre coastal wetland and marine conservation area. The San Diego Natural History Museum's trail guide counts more than 180 bird species there. Its winter visitors include migratory shorebirds, ducks, coots, pelicans, gulls and terns. Yellow-rumped warblers show up in the fall and winter brush.
eBird's checklist for the north side of the lagoon covers all years, so it is a list of species recorded there, not this week's sightings. The ducks on that list include Surf Scoter, Bufflehead, Common Goldeneye and Red-breasted Merganser. The shorebirds include Marbled Godwit, Dunlin, Least Sandpiper and Western Sandpiper.
The new bridge is also expected to help the habitat these birds use. SANDAG says the concrete replacement opens a wider channel under the tracks, which improves tidal flow. The project lets northbound and southbound trains pass each other at the lagoon, and lets passenger trains pass slower freight trains on the second track.
Walking the North Shore This Season
The City of Carlsbad lists the Batiquitos Lagoon trail as a 2.7-mile walking and hiking trail along the north shore. It has several access points, mostly along Batiquitos Drive. The trail and its picnic tables are open dawn to dusk. The Batiquitos Lagoon Foundation's Nature Center is at 7380 Gabbiano Lane. Its restroom and viewing deck are usually open 9 a.m. to 3 p.m., depending on volunteer availability. The California Department of Fish and Wildlife also points visitors to the end of Gabbiano Lane for trail access, and warns that public parking there is very limited. On event mornings, the Batiquitos Drive access points help spread out the parking.
The Foundation's docent tours cover lagoon habitats, birds, Indigenous heritage, insects, geology, the beach, the watershed and water quality. Its fall listings at the Foundation's site run through mid-December:
- Saturday, Oct. 17, 10 a.m. "Creepy, Crawly & Cool," a 60-minute docent walk about spiders and tarantulas, meeting at 7380 Gabbiano Lane.
- Saturday, Nov. 14, 10 a.m. "The Kumeyaay Through Time," part of the Foundation's second-Saturday speaker series at the Nature Center.
- Saturday, Nov. 21, 10 a.m. "The Kumeyaay Trail," a hike.
- Saturday, Dec. 12, 10 a.m. "Walk Among the Stars," also at the Nature Center.
The Foundation's regular one-hour docent walks are described as a third-Saturday event, but the calendar that lists them puts November's walk on Saturday, Nov. 14, 10 to 11 a.m. The Foundation's event pages also don't always print a year, and they sometimes still list programs that have already happened. Confirm the date, time and meeting spot for any of these 2026 programs with the Foundation before you go.
Where the Trestle Fits In
The trestle is easy to overlook because it has been part of the lagoon's west end for 80 years. KPBS's 2024 photo shows a Coaster crossing the single-track bridge, and that is how it looks today. Once trains move over, crews will take off the old track, rebuild the erosion protection around it and then demolish the wooden structure. Under the published schedule, all of that work falls in the months outside nesting season, the same months the museum's guide lists for the lagoon's winter visitors. Questions about specific work nights go to the SANDAG Build NCC team at [email protected] or 844.622.0050.
Chad and Yo Pagni follow projects like this one because they shape everyday life on the lagoon's north shore for years. If you live near Batiquitos Drive or La Costa Avenue and want to talk about what the double-track work means for your street and your home, Pagni Real Estate is glad to help. Schedule a free consultation and we'll go through it with you.
