25th Avenue Grade Separation Project

September 2021 marked the completion of the 25th Avenue Grade Separation Project.

Project History

In 1999, project planners started envisioning the 25th Grade Separation Project

The $205.9 million project was comprised of funding from the San Mateo County Transportation Authority, California High Speed Rail Authority, California State Department of Transportation (Caltrans), and the City of San Mateo. We are the sponsoring partner.

The project raised the train tracks, and slightly lowered the road (grade separated), at E. 25th Avenue, and created new east-west street connections at 28th and 31st avenues between S. Delaware Street and El Camino Real. As part of the project’s overall improvements, Caltrain has rebuilt a new elevated Hillsdale Station with updated amenities. The station re-opened on April 26, 2021. 

The project improved safety for both motorists and pedestrians, and reduced local traffic congestion in San Mateo. Construction began in 2017 with an official groundbreaking. The project was in conformance with the San Mateo Rail Corridor Transit Oriented Development Plan.

The project is currently assessing improvements for bike safety implementation on E. 28th Avenue between El Camino Real and S. Delaware Street. In May 2021, the project added new shared roadway markings (sharrows) for bicyclists while we continue to work to align this segment with the Bicycle Master Plan-designated Class I bike facility planned for the northern sidewalk. On June 30, 2021, we held a virtual community meeting. Find our presentation here or view the recording of the meeting. See our Frequently Asked Questions for additional information. 

Project Milestones

25th Grade Site Pics - - 31st Ave -  July 20 2021 On Aug. 27, 2021, the new E. 31st Avenue between El Camino Real and S. Delaware Street opened to the public. This new east-west connections marked the final road component of the project.

On Aug. 2, 2021, the improved E. 25th Avenue, between Palm Court and S. Delaware Street, re-opened. The road -- once an at-grade intersection -- is now separated from the rail tracks providing a safer crossing for all modes of travel. 

On April 26, 2021Night on 28th Avenue - Mar 1 2021 - JYu Photo, the new Hillsdale Station opened off the new section of E. 28th Avenue making it easier for residents and visitors to access Bay Meadows, Hillsdale Shopping Center and more of what makes San Mateo a great place to live and work.

On March 1, 2021, a new section of 28th Avenue opened between El Camino Real and S. Delaware Street. This new connectivity greatly improves the ability for our emergency vehicles to arrive quicker and our traffic to flow easier.

In November 2020, we added additional flashing pedestrian beacons at 28th Avenue and Paddock Way to provide greater visibility to pedestrians crossing the street at this location. Now each pedestrian crossing on 28th Street in Bay Meadows has an enhancement to improve pedestrian safety. 

Rail Bridges

On May 28, 2020, the first passenger train traveled above grade across 25th Avenue and Delaware Street. This milestone marked the beginning of the transition to a safer intersection in the neighborhood. 

In late-2019, the project installed rail bridges over 25th, 28th, 31st avenues, along with the pedestrian bridge to the future Hillsdale Station, a major step in the progression of the project. 

Watch the Rail Bridge Installations

Watch a time-lapse of each rail bridge installation: E. 25th Avenue in July 2019, 28th Avenue in September 2019 and 31st Avenue in October 2019

Past Presentations

In 2019, Caltrain made a project presentation to San Mateo City Council on July 15. Click here to view the presentation (starts at hour 2:30). In May 2019, Caltrain presented its latest project update to San Mateo’s S&I Commission (starts at minute 08:50).

Proposed pedestrian underpass at new Hillsdale Station rendering

Project Documentation