Cambridge & Somerville - Red Line Extension

The Red Line Extension marked the end of the era of mindless highway expansion. It was born in the ashes of the Inner Belt Project, which had sought to extend highway viaducts through the middle of Cambridge and the Fenway. After a public outcry and extensive planning discussions, highway funds were redirected toward the enhancement and extension of Red Line, to Quincy and Braintree on the south side, and from Harvard Square to Alewife on the northside.

The Red Line's NW Extension included 4 new stations and 3.2 miles of twin tunnels. Much of the project, including the tunnels from Harvard to Davis Square, and Porter Square station, was mined from below, almost invisibly.

This project is in many ways a model for the North South Rail Link. Construction was completed with minimal surface disruption, on schedule and within the projected budget, at a cost of about $1.6B in current dollars, far less than the benefits it has unlocked for Cambridge, Somerville and the western suburbs.

Aerial view of Harvard Square in Cambridge, showing the route of the Red Line Extension

The project included two new bored tunnels extending north from Harvard Square to Porter and Davis Square, and then to Alewife. Storage and repair yards that until the mid-1980's were located on the banks of the Charles River (lower left), were relocated. [© GoogleEarth]

Eliot Square Yard, looking from the tunnel entrance toward Harvard's Eliot House

With the extension of the Red Line, Harvard Square became a through-station rather than the end of the line, and these facilities were relocated. The Kennedy School of Government, Charles Hotel and JFK Park now occupy this site. [© Mark Solomon ca. 1972]

Aerial view of the Red Line Eliot Square yards in 1915

The tunnel entrance is visible in the upper left. [courtesy of Harvard University Archives]

Profile drawing of the Red Line NW Extension Project

The tunnels descend from Harvard Station to permit Porter to be mined within the Cambridge Argillite stratum, thereby avoiding the surface disruptions that plagued another local tunnel project. [Nathaniel Rogers]

JFK Park in Cambridge

JFK Park in Cambridge, on the banks of the Charles River, was once the site of a large train yard, where Red Line cars were repaired and stored overnight. [photo taken in May 2013 by JOgdenC]

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