MBTA Subway Lines: Red, Orange, Blue, Green, Silver

Boston runs the oldest subway in the country, and it shows in the best and worst ways. The lines are colour-coded, which is genuinely helpful, and then several of them split into branches, which is where visitors come unstuck.

The lines

Red Line runs from the northwest, through Cambridge and Harvard and MIT, under the river into Downtown, and then splits in Dorchester into two southern branches. Getting on a Red Line train southbound without checking which branch it takes is the classic first-week mistake.

Orange Line runs north to south through the middle of the city, from Malden down through Downtown and out to Forest Hills in Jamaica Plain.

Blue Line runs from Downtown northeast under the harbour toward Revere, and it is the line that serves Logan Airport, with a shuttle bus connection to the terminals.

Green Line is the oldest part and the most complicated: light rail, partly underground downtown and partly on the surface, splitting into branches lettered B, C, D and E that run out to different western and northern destinations. The Green Line Extension opened its Medford branch in December 2022, which is why the E branch now runs to Medford/Tufts and the D branch to Union Square in Somerville.

Silver Line is bus rapid transit rather than rail, though it appears on the rapid transit map. Some Silver Line routes serve the Seaport and Logan Airport.

The branch problem

The Green Line and the Red Line both split. This is the single most important operational fact for anyone new.

On the Green Line, a train's letter tells you which branch it serves. The lettered branches diverge west of the downtown tunnel, and boarding the wrong letter means a pleasant tour of a neighbourhood you did not intend to visit.

On the Red Line, southbound trains serve one of two branches, and the signage on the train tells you which.

The rule for both: read the destination on the front of the train, not just the colour on the map.

Getting to Logan

Two reasonable options. The Blue Line to Airport station, then the shuttle bus to the terminals. Or the Silver Line from South Station, which serves the airport directly and is convenient if you are coming from the south side of downtown.

Which is better depends entirely on where you start. From the north side, Blue. From South Station or the Seaport, Silver.

What to expect

This is an old system carrying a modern load, and the MBTA has been running an extended programme of track and signal work to address years of deferred maintenance. That work shows up as weekend shuttle buses and periodic closures of whole segments.

Check for planned diversions before you travel, especially on a weekend. A line that is on the map is not necessarily running trains on the day you want it.

The upside of the age is coverage: the network reaches into dense neighbourhoods that a newer system built around highways would have skipped entirely, and Boston is genuinely usable without a car in a way most American cities are not.