EYE ON:
California’s Cal Park Tunnel

Story and photos by Rails-to-Trails Conservancy.
This article appears on Rails to Trails magazine, Fall 2010

In Marin County, Calif., a large hillside separates most of San Rafael’s population from the ferry terminal at Larkspur Landing, a major access point for commuter ferries into downtown San Francisco. For years, bicyclists and pedestrians have had to take a circuitous route around and over this hill. Yet with a tunnel reconstruction project through the hill set for completion later this fall, pedestrians will soon have direct access to the Larkspur Ferry Terminal, as well as a future SMART (Sonoma Marin Area Rail Transit) station at the south portal.

More than 30 years in the making, the Cal Park Tunnel is a critical north-south link in Marin County. It will be the backbone of a system linking tens of thousands of North and South Marin residents to points in San Francisco and beyond. When the project is completed, including a total of 1.1 miles of new trail and connectors, the 1,100-foot tunnel will cut the bicycling time from San Rafael to the ferry from about 20 minutes to five—making it faster to pedal than to drive.

Originally constructed in 1884, the tunnel was part of the Northwestern Pacific line that carried freight and passengers to Tiburon and Sausalito. The tunnel was then expanded in 1924 to allow for double tracking and an electrified passenger trail. Freight continued to run on the line until the late 1970s, when Marin County purchased the corridor for future passenger rail and trail use.

The Marin County Bicycle Coalition (MCBC) made the tunnel reopening a top priority in 1998 and has led the advocacy effort ever since. “The opening of Cal Park Tunnel next year will turn a 20-minute, hilly and dangerous bike ride between San Rafael and the Larkspur Ferry Terminalinto a five-minute, safe and flat connection,” says Deb Hubsmith, advocacy director of the MCBC. “MCBC thanks the county of Marin and SMART for their leadership in building this visionary project. It will transform commuting options in Marin County.”

The tunnel is now in the final phase of construction. With more than $25 million in funding, work began on access to the tunnel last summer, says Dave Bernardi, Cal Park Construction project manager. He says linkages to the tunnel from connecting streets should be completed by August, and a grand opening is planned for later in 2010 (the final date is not set yet).

The Cal Park Tunnel has been a priority of Rails-to-Trails Conservancy’s (RTC) Western Regional Office for years. The project posed challenges that helped inspire RTC’s 2001 Tunnels on Trails report, prepared for the Marin County Board of Supervisors to address the safety and feasibility of reopening railroad tunnels for trails. The study, and RTC’s advocacy, played a key role in advancing the project.

To reconstruct the tunnel, all the wood timbers had to be replaced with steel arches encased in shotcrete embedded with small steel fibers to increase flexibility. The collapsed southern portion of the tunnel needed to be cleared of boulders and soil before the tunnel and hillside were rebuilt. The pathway itself will be 12 feet wide and striped for two-way traffic. It will be open from 5 a.m. to 11 p.m. and includes emergency call boxes and blue light stations, closed-circuit television cameras and a separate ventilation system from the main track, which will have diesel engines running on the line.

“When the tunnel opens, I predict it will be a showcase rail-with-trail project,” says Laura Cohen, director of RTC’s Western Regional Office. “It has it all: sophisticated tunnel design, an easy shortcut through the hills and a direct connection to the ferries that take you to San Francisco. Kudos to the leaders and advocates of Marin County in overcoming the design challenges to make this a reality.”

For more information on the Cal Park Tunnel, visit www.marinbike.org or call MCBC at 415.456.3469.