Corridor Crossings Strategy Logo


There are currently 71 ‘at-grade’ crossings along the Caltrain corridor, meaning an intersection where a road crosses railroad tracks at the same level. Caltrain is working with partners via the Corridor Crossings Strategy (CCS), including JPB member agencies, regional agencies, corridor jurisdictions, and the broader community, to identify areas for enhancement in the current grade separation project delivery process. The goal is to develop a corridor-wide approach to grade separation and/or rail crossing closure projects in order to elevate their importance in infrastructure funding as a shared regional responsibility.

It should be noted that current grade separations projects will continue in parallel to this effort. For information regarding active corridor projects, please refer to the interactive map.


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This section outlines the active projects which include grade separations and/or crossing closures along the corridor as well as the current stage of the project. The main project stages include Planning, Environmental, Design, and Construction and are each defined below. For more specific information on these active projects, please refer to the interactive map. It should be noted that the completion of these active projects is dependent on securing funds which could take years to obtain.


The planning phase includes the initial stage of conceptual design. This phase includes coordination with the sponsoring agency, gathering of project-related data, obtaining of internal and external feedback on the proposed project and review of early conceptual designs. This phase also includes as assessment of potential impacts to Caltrain facilities, including operations, maintenance and access, as well as review of community engagement and outreach materials.  


The environmental phase and its corresponding environmental studies are normally conducted in tandem with the early engineering design phase, when sufficient engineering detail is available to  support these studies. The environmental studies involve identifying and verifying any potential impacts to the environment associated with project implementation and developing corresponding mitigation measures to avoid or minimize potential impacts. 


This phase, through multiple design iterations demonstrates how a project’s design meets the needs and objectives of the project, while also adhering to the quality control and quality assurance process established by Caltrain. During this process, designers also demonstrate how the designs meet the regulatory requirements such as American with Disabilities Act (ADA) compliance, stormwater management and sustainability design.  


The construction phase begins after completion of design and construction procurement.  At this point, jurisdictions will have secured all project funding, acquired all necessary right-of-way (ROW), and obtained all applicable permits. In the construction phase, Caltrain administers the advertisement and selection of the contractor to build the project. Caltrain oversees the construction process as other agencies are not allowed to perform or oversee construction on Caltrain’s active rail corridor. This phase is completed once construction is finished, the project is operational, and all maintenance agreements have been secured.

CCS Project Timeline Tracking Table

The existing Caltrain corridor consists of 77 miles extending from San Francisco to Gilroy. Caltrain owns and operates 52 miles of the corridor from the 4th and King Station to the Tamien Station. The Union Pacific Railroad (UPRR) owns and operates 25 miles from south of the Tamien Station to the Gilroy Station.

Corridor Crossings Strategy Summary Infographic


The CCS was originally identified as part of the Caltrain Business Plan to enhance the current grade separation process and develop corridor-wide consensus on a strategy to deliver grade separation projects at the regional scale. Currently, projects are implemented on a project-by-project basis and funding is largely first come, first serve. This effort will be partner-led and directed process with the goal of the following outcomes:

  • Develop a Crossings Delivery Guide that defines, communicates, and facilitates a clear project delivery process
  • Implementable, shared vision for safe and reliable grade-separated rail service
  • Identify investment needs and a well-positioned program for funding opportunities
  • Strengthen partnerships between Caltrain, regional member agencies, and local jurisdictions

The Crossings Delivery Guide will be developed as a user-friendly, web based guide to clearly define processes, procedures, roles, and the responsibilities of Caltrain and local partners in implementing the grade separation or closure of an existing crossing. More information is to come once the Crossings Delivery Guide is completed.

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Passenger rail service has been running along the Caltrain corridor for over 150 years. Communities and job centers have grown around the corridor since service began, with the Bay Area's population growing by over 113% since the 1960's. This growth and build out can be seen below, with smaller communities such as Mountain View and San Bruno evolving into major employment and population centers today. According to Caltrain’s Business Plan, the corridor is expected to add 1.2 million people and jobs within 2 miles of the Caltrain corridor by 2040. Corridor-wide demand is also expected to increase from 60,000 daily riders today to 150,000-200,000 weekday riders. Transit is an essential transportation mode throughout the changing region, and these impacts create new circulation and mobility challenges that require a modern, improved corridor. 

Grade separations or closures can mitigate these impacts and provide broader community benefits. Through separating the rail corridor from the roadway, grade separations or closures can improve community circulation and help pave the way for enhanced multi-modal transit. 

The planning for, funding, and construction of grade separations has been an issue throughout the corridor's history. Currently, grade separation projects are developed on a project-by-project basis, initiated by individual cities. Available funding sources also pale in comparison to the existing corridor demand, leaving projects to effectively compete against each other for funding. A coordinated corridor-wide strategy could resolve these challenges, and potentially better position crossings projects for additional funding opportunities.  

San Mateo Before and After Aerial of City

Aerial along B Street, San Mateo, CA, in 1940 (image via San Mateo Local History Collection) vs today (image via Google Earth).

CCS Before and After of San Antonio Road in Mountain View

Aerial of San Antonio Road, Mountain View, CA in 1965 vs now. (image via

Crossing Types

Types of grade crossing


Crossing Separation or Closure Benefits

Benefits of grade separation and closures


  • Improved Safety : Eliminating conflicts between trains, vehicles and active transportation improves safety for multi-modal travelers. 
  • Reduced Noise: Grade separations or closures eliminate the need for train horns to sound when approaching an at-grade crossing, reducing noise for the surrounding community. 
  • Decrease in Traffic Congestion: Congestion decreases with a grade separation or closure since vehicle and active transportation travelers are not left waiting at railroad gate arms. 
  • Reduction in GHG Emissions : Closing or grade separating a crossing reduces GHG emissions, due to vehicles not needing to idle because of passing rail traffic. 
  • Improved Train Operations Reliability: Train operations improves with a grade crossing or closure since trains do not have to stop or slow down due to other travel.
  • Enhanced Community Connectivity: Community connectivity and multi-modal transit opportunities improve with the removal of the conflict with the train corridor, allowing for smooth travel across the railway.