I just came back from Boston and ended up riding each line that the MBTA provides in the Boston area except for commuter rail and some heritage railway I didn't need to use. Because of how weird the entire network is itself, I have a thought on each line in a sort of roasting-like manner.
The whole network is weird to me because no single line runs the same type of vehicle as another. This is a bit baffling coming from a city where there are three lines and two of them use the same train types. That and the headways between trains just makes it so awkward.
At least this visit to Boston unlike the last one had all of the lines as functioning although on the weekend one line was running with a shuttle bus between two stations.
Red Line
Braintree and Alewife are termini? These names are just wild. This is probably the most normal of the lines I rode
Blue Line
Wonderland is the name of a terminus? I have never been in a subway where not only do the platforms curve upward but also to a side. That is some impressive engineering.
Orange Line
Nice to know that trains can catch fire and not manage to kill anyone. Why does this line run so slowly again?
Green Line
Good lord. This line is weird. Level-crossings for pedestrians isn't so weird, but it is extremely weird when they're inside of the subway itself. Also, is this a subway or a tram? The use of low-floor trains kind of remind of Brussels' tram network, but these cars are nowhere near as elegant.
Also the Green Line has the most obtuse setup I have ever seen. Hope you pay attention to which letter you're taking on that line because there are four going west and two going east.