Tonight marks the last time the T will use the current Lechmere station for anything trolley related. It shuts tonight and in 11 months or so, there'll be a brand-new station nearby as the current tracks are extended towards Somerville.
Of course, what comes down must have gone up. The current station opened on July 10, 1922, one of the first parts of what the Boston Elevated Railway thought would be a bold expansion plan that would include a new rapid-transit line extending all the way into Somerville. Ahem, and here we are almost 98 years later.
The ultimate reason for the station, though, was not to become a portal to the Green Line Extension of the future, but to deal with a more immediate, more pressing El problem: Too many trolleys funneling into Boston on the viaduct that went up across the Charles in 1912 (the same viaduct that is now being extended north).
Back then, the El ran something like two dozen trolley lines, including ones from Somerville and Harvard Square that stopped at the previous Lechmere station and just kept going into Boston - where the central tunnel that formed the heart of the area trolley system just couldn't handle all the trolleys. In 1921, the El began construction of a new station at Lechmere that would serve as a sort of dual terminal: People coming from Harvard Square and Somerville would have to get off their trolley at Lechmere and transfer to another trolley from there into Boston.
The City of Boston Archives, which inherited Boston Elevated Railway files, has a number of photos of the station's construction:
March 18, 1922 (source):
More construction (source):
After the station opened - note the streetcars coming in from the north at the top left (source):
Cambridge did not much appreciate the new station: In 1921, the City Council authorized the city lawyer to sue to try to stop construction. That failed. In March, 1923, a Cambridge city councilor declared the station's basically open layout meant riders froze in the winter and got soaked in the rain and said he wouldn't be surprised if people would die from the conditions there.