The long-awaited plan to untangle Caltrain tracks from street traffic at South Linden Avenue in South San Francisco and Scott Street in San Bruno just got a leaner price tag. After a redesign that shaved about $130 million off earlier estimates, the grade separation project is now expected to cost roughly $320 million.
The San Mateo County Transportation Authority (TA) pushed the effort forward in early May when its board approved Measure A funding to kick off preliminary engineering. Under the updated concept, South Linden would be dropped under the railroad while Scott would be closed to vehicles and rebuilt as a pedestrian-and-bike undercrossing.
The savings and the design pivot were laid out at the TA board’s May 7 meeting, where directors signed off on nearly $3.7 million in Measure A money and staffer Patrick Gilster told the board the plan "improves traffic circulation and mobility," as reported by the San Mateo Daily Journal. TA staff recommended programming $2,804,490 from the Measure A Grade Separation Category and $860,625 from the Measure A Caltrain Category to cover preliminary engineering and environmental clearance, according to a staff report from the San Mateo County Transportation Authority.
What changed in the design
The redesign essentially flips the earlier game plan. Instead of elevating the rail line at Linden and raising it slightly at Scott, engineers now intend to lower South Linden beneath the tracks and permanently close Scott to cars, replacing it with a pedestrian and bicycle undercrossing, according to the City of San Bruno project page.
Both cities and Caltrain settled on a preferred alternative in an April 2021 Project Study Report and have since been running the numbers and tweaking the details through value engineering to refine costs and impacts, the South San Francisco project page notes.
Money and timeline
The new configuration trims roughly $130 million from the budget, bringing the current construction estimate down to about $320 million. "Reducing the project by $130 million is really a big deal," Board Member and South San Francisco Councilmember Mark Nagales told colleagues, according to the San Mateo Daily Journal.
Preliminary engineering is slated to wrap up in June 2027. Construction is expected to take about two to three years after environmental clearance, the outlet reported.
Why it matters for drivers and riders
South Linden is the only at-grade Caltrain crossing inside South San Francisco, and Scott sits less than a mile away, which means the two locations have to be tackled as a package so one fix does not create a new traffic nightmare a few blocks over, the City of San Bruno explains.
Caltrain planning documents and the cities’ studies point to potentially significant expansion of Peninsula rail service toward 2040. More trains would mean more gate downtime at crossings, which in turn raises the stakes for separating tracks from cars, bikes and pedestrians to keep traffic moving and improve safety.
Next steps include finalizing consultant contracts, completing environmental review and returning to the TA board as design details are sharpened and cost estimates are updated. The TA staff report authorizing the Measure A funds gives the cities and Caltrain room to keep value engineering the project while trying to stay within that newly trimmed budget.
