Twin Peaks Tunnel Work to Start November 30

Twin Peaks Tunnel Work to Start November 30
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View from inside the Twin Peaks Tunnel that was first opened 102 years ago in 1918 

The Eureka Curve is a section of the Twin Peaks tunnel that connects downtown San Francisco to West Portal and beyond. In 2019, we completed a major project in the Twin Peaks tunnel with seismic upgrades, major track and other infrastructure overhauls. Now, additional work in this crucial section of trackway needs to be done, and we will start that on Monday, November 30. This work is essential to improving the quality of the system and reducing the potential for disruptions to service in the years to come. 

Starting the Monday after Thanksgiving, construction crews will begin maintenance work inside the Twin Peaks Tunnel going into the tunnel via the entrance on Market Street between Diamond and Collingwood Street. Planned work includes replacement of the overhead catenary system (OCS) splice connectors, overhead lines, track fasteners, rails, track ballast, switch machine, trackway adjustment throughout the tunnel, rail grinding, installation of new subway lights, and several trackway and OCS tests. These are the key elements that keep our trains running. 

Work is planned for approximately three months, through February 2021. Crews will take a break for the holidays from December 24th through New Year's Day. Construction is scheduled for Monday to Saturday, from 7:30 a.m. to 8 p.m. with hours are subject to change based on construction needs. No night work will occur in the public right of way and will be limited to inside the tunnel. 

As we perform this work, some parking will be temporarily restricted, and traffic lanes will be modified in the construction zone near Castro Station: 

• One lane street closure in each direction on Market Street between Diamond and Castro Street during active construction hours 
• Parking will be temporarily restricted on Market Street between Diamond and Castro Street  
• No access to Market Street from Collingwood Street. Local access to Collingwood Street 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 mornings for about an hour. We do not anticipate any parking impacts or traffic lane changes near West Portal Station.  
• This work is part of our Subway Renewal program that targets critical subway systems and infrastructure for strategic overhauls to improve system reliability and resilience. This work will improve the maintainability of the trackway. It will also provide a more solid foundation for service into the future.  

Ballast Replacement Details 

Ballast is the rocky bed beneath the tracks that stabilizes the trackway. Over time, the ballast wears and can become dusty as the larger rocks are broken down, these are called fines. Over time the number of fines increases, and the trackway can become muddy and difficult to maintain. During the 2019 Twin Peaks project, we reused rather than replaced the ballast in an attempt to save time and money. Unfortunately, the required procedural steps to ensure that the reused ballast would maintain its integrity through a thorough wash/filtering process was not followed. Looking back, we acknowledge these choices were an oversight.

Example of ballast – the rocks that help stabilize the tracks  

Today the ballast has continued to degrade and will, over the long term, reduce the expected life of the new trackway if left unaddressed. In order to take advantage of the current closure of the subway and minimize future disruptions to service, we are moving ahead with the ballast replacement now.  

This issue also underscores two of the key areas we are targeting with our Subway Renewal program: improved project delivery and workforce culture. The decision-making process that led to the reuse of the ballast in 2019 should have been interrogated more intensively. We are committed to promoting a more open workplace that supports our staff raising challenging questions during the course of projects to make sure the choices we make are in the best interest of the system and of the public.  

We thank San Franciscans and Muni customers for your continued patience and understanding as we navigate through our Subway Renewal program and work towards the return of rail service. We will keep you informed about our continued efforts at SFMTA.com/RailRecovery. 

Published November 21, 2020 at 05:29AM
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Twin Peaks for All: Survey Results

Twin Peaks for All: Survey Results
By Benjamin Barnett

Last month, the SFMTA and San Francisco Recreation and Parks Department released a survey seeking public feedback regarding five proposed roadway options for Twin Peaks Boulevard. San Franciscans responded to the survey, ranked support for each alternative and shared opinions about how the different options met their needs. 

The Twin Peaks for All survey was open for almost three weeks and received more than 1,700 responses. This number reflects the high level of interest for this San Francisco park and its future access.  

Survey Background

Conditions on Twin Peaks Boulevard between Portola Drive and Barnett Avenue before COVID street closures.  

The Twin Peaks Boulevard gates were closed early in the pandemic to reduce crowding at the lookout point parking lot. The gates were closed on the north, at Burnett Avenue, and the south, at Portola Drive. Since then, Twin Peaks Park use by hikers, joggers and people on bicycles has increased significantly, with an average of more than 800-weekday visitors and more than 1,100-weekend visitors.  

While the new park access configuration received support, there are also significant community concerns. Our goal with the new design proposals and survey is to find a solution that balances all the various needs of the community including people with disabilities, neighbors and everyone that enjoys this iconic park. 

Survey Options:

1. Burnett Avenue - Burnett Avenue gate is open 24 hours, with parking and a vehicle turnaround available on Christmas Tree Point Road.  
2. Portola Drive - Continue keeping the Portola Avenue gate open, extending the hours from noon to midnight daily.  
3. One-Way Southbound - One-way, southbound vehicle traffic, from the north gate at Burnett Avenue to the south gate at Portola Drive. Reserve the northbound vehicle travel lane for people walking and bicycling.   
4. One-Way Northbound - One-way, northbound vehicle traffic, from the south gate at Portola Drive to the north gate at Burnett Avenue. Reserve the southbound vehicle travel lane for people walking and bicycling.  
5. Pre-COVID - Open both the north and south gates, as were conditions pre-pandemic. The east side of the figure eight is reserved for people walking and biking and the west side of the figure eight is reserved for two-way traffic.   

Overview of Results:

Map representing the Burnett Avenue Option, the most preferred option according to the survey. 

• The Burnett Avenue Option was most preferred with 52 percent of people ranking it highest in comparison to the other four options 
• The Pre-COVID Option was the most divisive of the five options, it ranked as the second most preferred with 30 percent but also most respondents ranked it as less preferred with 64 percent of the vote.
• Mode of transportation to Twin Peaks was associated with responses, with visitors traveling by non-motor vehicular modes favoring the Burnett Avenue Option and visitors traveling by motor vehicular modes favoring the Pre-COVID Option 
• Many respondents commented that they prefer some form of car-free space on Twin Peaks 
• Survey respondents are concerned about sharing the road to the top of Twin Peaks with tour buses and motor vehicle traffic 
• Crime, vandalism and litter are concerns associated with all options 

What We Learned from You

Many people who filled out the survey are regular visitors to the area; almost 50 percent of the respondents typically visit Twin Peaks one or more times per week with another 27 percent of people who visit once per month. People who took the survey tend to reside near the park. The highest percentages of respondents came from zip codes immediately adjacent to the park and of the more than 1,700 responses, 50 respondents were from outside of San Francisco. In total, 52 percent ranked the Burnett Avenue option as their preferred choice. The next closest preference was the Pre-COVID option, with 30 percent.  

Other data demonstrating Option 1 was the most preferred include:  

• Trip frequency did not have an impact on preference, from the respondents stating that they rarely/never visit Twin Peaks to those visiting 1-4 times a week, Option 1 was preferred.  
• Most respondents 64 years of age or younger preferred Option 1.Those 65 years of age or older preferred Option 5.  
• Option 1 was the top preference across races/ethnicities.

More to Come

Access to Twin Peaks is important to San Franciscans and this was reflected by the large number of responses and the range of responses to the Twin Peaks for All survey. Responses reflected that both personal and property safety is important as is access to the beautifully scenic resource. For a much more detailed analysis of our survey data please visit our survey report.

SFMTA staff will continue to review the options, working with project stakeholders to develop a project that is feasible and meets the needs of the public based on the survey results. Staff will develop a final proposal to share with the community and present to the SFMTA Board of Directors for potential approval in the coming months.   Twin Peaks is a beautiful and unique destination for San Francisco residents and visitors alike and everyone should have the opportunity to enjoy it. For more information or to sign up for an email update, visit our project page.  

Published November 20, 2020 at 05:05AM
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