UPDATE: IB and OB 38/38R continue to reroute around Geary and 38th due to non-Muni collision. (More: 8 in last 48 hours)

Eureka Curve Tunnel Work

Project Introduction

Eureka Curve Tunnel Work is underway! To improve the subway’s reliability and resilience, crews will use this maintenance window while the subway is closed to replace track, ballast, crossovers, and switches throughout the Twin Peaks Tunnel between Castro and West Portal Station.

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Project Timeline 
November 30, 2020
Construction begins
February 2021
Anticipated project completion
Predicted Completion
February 2021
Project Status
Implementation / Construction
Project Details, History or Features

In 2019, we completed a major project in the Twin Peaks Tunnel that included seismic upgrades and major track and other infrastructure overhauls. Additional work in this crucial section of trackway still needs to be done to improve the quality of the system and reduce the potential for disruptions to service in the years to come. 

Starting Monday, November 30, construction crews will begin maintenance work inside the Twin Peaks Tunnel. Most materials and equipment will enter the tunnel at the Eureka Curve – the area on Market Street between Diamond and Collingwood streets.

Planned work includes: replacement of the overhead catenary system (OCS) splice connectors, track ballast, overhead lines, track fasteners, rails, switch machine, trackway adjustment throughout the tunnel, rail grinding, installation of new subway lights and several trackway and OCS tests.

The Eureka Curve Tunnel work is anticipated to take approximately three months. Crews will take a break from December 24th to New Year’s Day and plan to wrap up in February 2021.

Construction work is scheduled for Monday to Saturday, from 7:30 a.m. to 8:00 p.m.; hours are subject to change based on construction needs. No night work will be performed in the public right of way and will be limited to within the tunnel. Heavy equipment will be entering through West Portal subway tunnel only during the morning, for about an hour. We do not anticipate any parking impacts or traffic lane changes near West Portal Station.

As we perform this work, some parking will be temporarily restricted, and traffic lanes will be modified in the construction zone. These temporary changes are:

  • One lane street closure in each direction on Market Street between Diamond and Castro Street
  • Parking will be temporarily restricted on Market Street between Diamond and Castro Street  
  • No access to Market Street from Collingwood Street. Local access from 18th Street will be provided 
  • Material and equipment staging on both sides of Market Street between Diamond and Collingwood Street.  
  • Heavy equipment will enter through West Portal Station tunnel most morning for about an hour. We do not anticipate any parking impacts or traffic lane changes near West Portal Station.
Contact Information
Jerri Diep