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Caltrain Grade Separation Feasibility Study

Sunnyvale has active, street-level railway crossings at Mary and Sunnyvale avenues. We will review options for separating the road and railway. We'll study safety concerns, traffic backups, improving pedestrian and bike access, and reducing noise impacts.

Grade separation means adding a structure which separates a roadway from a railway. The structure would be below or above the original street level ("grade"). View an image, "project options," on the Details tab.


Angela Obeso, Principal Transportation Engineer, 408-730-7557


The City is refining the design options and finalizing the traffic analysis. We will hold community meetings in early 2022.


Caltrain Railroad Crossing Locations

For each option, we will analyze existing and future traffic conditions. The project will identify the pros and cons of each option and potential solutions.

We are analyzing the following project options (images):

  1. Mary Avenue Underpass Tunnel
  2. Mary Avenue Underpass Tunnel with Jughandle
  3. Sunnyvale Avenue Underpass Tunnel
  4. Sunnyvale Avenue Underpass Tunnel for Bicycle and Pedestrian Undercrossing


The following materials have been presented on this project: 

Report to Council 17-1161, Jan. 23, 2018 - City Council Consideration of Rail Depression Alternative for Caltrain Grade Separation, Approval of Budget Modification, and Authorization of City Manager to Execute Contract Amendment with BKF Engineers, Jan. 23, 2018

Joint City Council-BPAC Study Session 17-0578, Oct. 17, 2017 (10 MB PDF) - Presentation of Caltrain Grade Separation Feasibility Study

Community Meeting for Sunnyvale Avenue Grade Separation, Aug. 24, 2017 (10 MB PDF) - Presentation Material for Sunnyvale Avenue Community Kickoff Meeting

BPAC Working Session 17-0811 Presentation, Aug. 17, 2017 (12 MB PDF) - Presentation Material of Railroad Crossing Community Meeting

Community Meeting for Mary Avenue Grade Separation, Aug. 10, 2017 (4 MB PDF) - Presentation Material for Mary Avenue Community Kickoff Meeting

Report to Council 17-0055, Jan. 31, 2017 - City Council Approval of Contract with BKF Engineers to Prepare the Caltrain Grade Separation Feasibility Study

The Caltrain Grade Separation project is based on the following policies:

City of Sunnyvale Land Use and Transportation Element (LUTE) 2017
(Policies 24, 36, 40, 42 and 46 on safety, Policies 32 and 42 on transportation system efficiency, and Policy 42 on promoting regional commuter rail) (19 MB PDF)


The Caltrain railroad corridor provides regional rail transit services and relieves roadway traffic. Motorists and bicyclists crossing railroad tracks face high traffic delays in peak periods. This traffic delay is due to trains crossing at the same level as the street levels ("at-grade").

The at-grade train crossings force roadway traffic to wait due to:

  • Downtime of railroad gates
  • Frequency of train crossings resulting in more stops

Caltrain has three projects planned along the corridor (list below). These plans will allow Caltrain to run trains faster and improve service speeds. For motorists, bicycles, pedestrians and high-occupancy vehicles (such as buses and shuttles) this means increased congestion and delays.

To reduce delays the City is proposing grade separated crossings. Separating adjacent roadways from the railroad tracks provides many benefits such as:

  • Reducing or eliminating potential collisions
  • Removing the need to stop and wait for the rail gates
  • Reducing delays and congestion
  • Eliminating train horns and crossing bells (reducing noise)

In 2017 the City of Sunnyvale began a grade separation feasibility study (RTC 17-0055). The City performed public outreach in summer 2017. In Oct. 2017 the City Council and BPAC held a joint meeting for an update and provided feedback. The project team used the feedback to narrow down the design to four options. Some community feedback included interest in a full rail tunnel option.

In Jan. 2018 the project team presented these options to the City Council (RTC 17-1161). City Council considered adding a full rail tunnel option to the study. This option was found not feasible due to neighborhood impacts, construction operations and lack of funding. The City Council directed staff to study the original four design options (see Details tab).

Last Updated: Oct 27, 2021