The Tunnels and Trains

The tunnels would be constructed with tunnel boring machines. These boring machines can be built to any specifications needed. The use of one large tunnel with two tracks or two separate tunnels would depend ultimately on cost and required tie in with the North/South rail project. Tunnel construction would begin at Logan Airport and run west. The material excavated from the tunnel which is not used for tunnel wall construction would be removed and used for construction projects in the city.

Because the tunnels do not need to follow the topography of the land above, they can be built without any steep grades or sharp curves. The tunnels would generally be deep tunnels to minimize vibration and interference with utilities. They would rise closer to surface for stations. Only the Route 495 station would be at a depth needing high speed elevators.  The train design would depend upon the ultimate overall design and tie in with the rest of the commuter rail system as well as new technology that becomes available when it becomes time to build them. The train sets would probably only need to have a top speed of 150 -160 mph in order to maintain an average speed of 80-90 mph. Although a little slower, the new Beijing Metro trains are a good model. They are electric driverless trains with a capacity of 1,538 passengers. Each train has two sets of four cars, with one car designated as business class. One train set can be run in non-rush hour times. Because of the gentle grade and curves of the tunnels less power is used