Why Tunnels?
Just look at the time, permitting and political cost of the Green Line extension to understand why large infrastructure projects have become so costly. It’s not that we do not need them, but the idea of undertaking them spans more political cycles then most politicians care to tackle.
Here are the advantages of the tunnels:
No (or little) land taking. Tunnels would run under the Massachusetts Turnpike and Route 9 and other publicly owned property;
No need to run tracks around obstacles;
No vertical grade issues;
No traffic or other disruption during construction as 80% of work is underground;
Little or no environmental permitting, no Wetlands issues, no endangered species issues;
No noise, dirt during construction;
No noise or dirt during operation;
No abutter objections;
No level crossings or other above ground traffic dangers;
No weather issues for operations;
Less maintenance from weather issues;