Structural Study Moving Forward Another Step Towards Opening Alto Tunnel

Efforts to open Alto Tunnel–the historic rail route and potential key linkage for Marin’s bicycle network between Corte Madera and Mill Valley–reached another milestone this week.

The Marin County Board of Supervisors on Tuesday authorized the execution of a contract for the Alto Tunnel Geotechnical and Structural Investigation Study. The study will evaluate the tunnel’s interior and provide accurate costs associated with reconstructing the tunnel and opening it to bicycle and pedestrian access. According to the Alto Tunnel Study webpage, the study’s findings should be available in late 2017.

The contract comes more than five years after the Board originally accepted grant funds to prepare studies examining property rights and structural needs. The property study was completed in 2015, leaving the geotechnical study as the last major information-gathering hurdle to clear before pursuing funds needed to bring the project to fruition.

Since the 1970s, the County has had plans for a North-South Greenway utilizing the Northwestern Pacific Railroad right-of-way. This particular segment of the Greenway is a top priority for MCBC given the lack of viable alternatives. The current gap between the two towns forces people to bike over Camino Alto or Horse Hill, neither of which satisfy the needs of people of all ages and abilities due to topography, indirectness, and lack of separation from vehicular traffic.

Those who would like to get involved with advocacy efforts to open the tunnel can visit the Friends of Alto Tunnel’s website.

(Photos below are of the North and South entrances to the Alto Tunnel, during operation.)

altotunnel_northend_yearnotknown altotunnel_southend_yearnotknown

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