"The attached analysis assesses the technical feasibility of constructing a trench or a tunnel through all or
a portion of Palo Alto to place Caltrain (and High Speed Rail) below ground. The analysis indicates that trenching and tunneling would be feasible from an engineering perspective. However, there are a number of significant issues associated with trenching or tunneling throughout the entire City, making it very difficult for the City to obtain approval for or construct these alternatives. Principal issues, which are identified below, include construction impacts, necessary agency approvals, construction costs, and on-going operational/maintenance costs.
Trenching under a portion of the City - specifically the Meadow and Charleston crossings or just the Charleston crossing may be more feasible, but would require further analysis as we continue our planning process including review by the Technical Advisory Committee (TAC) of agency staff."