By 1922, the BERy believed that Harvard would be the permanent terminus; the heavy ridership from the north was expected to be handled by extending rapid transit from Lechmere Square.
The 1926 Report on Improved Transportation Facilities in the Boston Metropolitan District proposed an extension from Lechmere to North Cambridge via the Southern Division and the Fitchburg Cutoff, with a possible further extension along the Lexington Branch.
An extension of the Cambridge–Dorchester Line under Mount Auburn Street to Watertown, and thence along the Watertown Branch to Waltham, was also raised as a possibility.
A northwards extension from Harvard to the North Cambridge/Arlington border was proposed by Cambridge mayor John D. Lynch in 1933 and by then-freshmen state representative Tip O'Neill in 1936, but was not pursued.

The 1945 Coolidge Commission report – the first major transit planning initiative in the region since 1926 – recommended an extension from Harvard to Arlington Heights via East Watertown.
The 1947 revision recommended an extension north to Porter Square instead, with branches along the Fitchburg Division to Waltham and the Lexington Branch to Lexington.
The 1966 Program for Mass Transportation by the 1964-created MBTA called for an immediate extension to Alewife Brook Parkway via Porter Square, with possible future extensions to Arlington or Waltham.
Original plans called for a subway under Massachusetts Avenue to Porter Square, then a surface route along the Fitchburg Route to Alewife.
In the late 1960s, the project was expanded to follow the Lexington Branch to a terminal at Route 128.

In 1970, Cambridge began advocating for the project, and for the consideration of an all-subway route under Garden Street.
That October, then-governor Francis Sargent suspended most highway construction inside Route 128 and created the Boston Transportation Planning Review, which focused on the implementation of new transit routes.
In 1972, a new all-subway route via Porter Square and Davis Square was considered (and ultimately chosen).
By the mid-1970s, the project was split into two phases: an all-subway extension to Arlington Heights via Alewife, with a later extension to Route 128.

Arlington did not wish for Arlington Heights to be even a temporary terminal.
In March 1977, Arlington voters rejected the project in a nonbinding referendum, citing fears of increased taxes and congestion.
A May 1977 state bill prohibiting extension into Arlington was vetoed by then-governor Michael Dukakis.
The Environmental Impact Statement, released in August 1977, primarily evaluated the Arlington Heights terminus but also provided for a shorter Alewife extension.
By the time the northwest extension began construction in 1978, opposition in Arlington and reductions in federal funding had caused the MBTA to choose the shorter Alewife alternative.

The Red Line was extended temporarily to Harvard–Brattle over former yard and storage tracks on March 24, 1979.
This allowed for bus transfers to be provided.
The Harvard bus tunnel was closed temporarily at the time.
On January 31, 1981, the original Harvard station was permanently closed, as its demolition was required.
To replace it, a temporary station at Harvard–Holyoke was built across the tracks.
The two temporary stations were closed on September 2, 1983 in preparation for the opening of the new Harvard station.
On September 6, 1983, the new station at Harvard opened, with trains changing direction at Davis Square without carrying passengers.
Eliot Yard was demolished; Harvard's Kennedy School of Government now sits inside its retaining walls.

The line was extended to Davis with a station at Porter on December 8, 1984.
The line was extended to its current terminus at Alewife on March 30, 1985.
At the time, all off-peak trains terminated there, but due the incomplete construction of a yard at Alewife, only Ashmont trains ran to Alewife during rush hours.
Davis was the terminal for rush hour Braintree trains.
These trains were finally extended to Alewife during rush hours on December 26, 1985,
By 1922, the BERy believed that Harvard would be the permanent terminus; the heavy ridership from the north was expected to be handled by extending rapid transit from Lechmere Square. The 1926 Report on Improved Transportation Facilities in the Boston Metropolitan District proposed an extension from Lechmere to North Cambridge via the Southern Division and the Fitchburg Cutoff, with a possible further extension along the Lexington Branch. An extension of the Cambridge–Dorchester Line under Mount Auburn Street to Watertown, and thence along the Watertown Branch to Waltham, was also raised as a possibility. A northwards extension from Harvard to the North Cambridge/Arlington border was proposed by Cambridge mayor John D. Lynch in 1933 and by then-freshmen state representative Tip O'Neill in 1936, but was not pursued.
The 1945 Coolidge Commission report – the first major transit planning initiative in the region since 1926 – recommended an extension from Harvard to Arlington Heights via East Watertown. The 1947 revision recommended an extension north to Porter Square instead, with branches along the Fitchburg Division to Waltham and the Lexington Branch to Lexington. The 1966 Program for Mass Transportation by the 1964-created MBTA called for an immediate extension to Alewife Brook Parkway via Porter Square, with possible future extensions to Arlington or Waltham. Original plans called for a subway under Massachusetts Avenue to Porter Square, then a surface route along the Fitchburg Route to Alewife. In the late 1960s, the project was expanded to follow the Lexington Branch to a terminal at Route 128.
In 1970, Cambridge began advocating for the project, and for the consideration of an all-subway route under Garden Street. That October, then-governor Francis Sargent suspended most highway construction inside Route 128 and created the Boston Transportation Planning Review, which focused on the implementation of new transit routes. In 1972, a new all-subway route via Porter Square and Davis Square was considered (and ultimately chosen). By the mid-1970s, the project was split into two phases: an all-subway extension to Arlington Heights via Alewife, with a later extension to Route 128.
Arlington did not wish for Arlington Heights to be even a temporary terminal. In March 1977, Arlington voters rejected the project in a nonbinding referendum, citing fears of increased taxes and congestion. A May 1977 state bill prohibiting extension into Arlington was vetoed by then-governor Michael Dukakis. The Environmental Impact Statement, released in August 1977, primarily evaluated the Arlington Heights terminus but also provided for a shorter Alewife extension. By the time the northwest extension began construction in 1978, opposition in Arlington and reductions in federal funding had caused the MBTA to choose the shorter Alewife alternative.
The Red Line was extended temporarily to Harvard–Brattle over former yard and storage tracks on March 24, 1979. This allowed for bus transfers to be provided. The Harvard bus tunnel was closed temporarily at the time. On January 31, 1981, the original Harvard station was permanently closed, as its demolition was required. To replace it, a temporary station at Harvard–Holyoke was built across the tracks. The two temporary stations were closed on September 2, 1983 in preparation for the opening of the new Harvard station. On September 6, 1983, the new station at Harvard opened, with trains changing direction at Davis Square without carrying passengers. Eliot Yard was demolished; Harvard's Kennedy School of Government now sits inside its retaining walls.
The line was extended to Davis with a station at Porter on December 8, 1984. The line was extended to its current terminus at Alewife on March 30, 1985. At the time, all off-peak trains terminated there, but due the incomplete construction of a yard at Alewife, only Ashmont trains ran to Alewife during rush hours. Davis was the terminal for rush hour Braintree trains. These trains were finally extended to Alewife during rush hours on December 26, 1985,
Red Line (MBTA)