There are no 'express' signs on the train-you have to listen for the driver's announcement, which could come at anytime. They aren't really as unique as trains, although they do hold some interesting stories, like the one about a man who punched his son in the face, drawing blood, while passengers and the driver sat by and watched as he got off the train. He was later caught after a passenger finally found his balls. The MBTA also has a commuter boat shuttle that cruises the harbor, making stops at Logan airport and the wharfs near downtown. People read on the train all the time.
People also do other things besides read on the train.
They also have stairs, if anyone is stupid enough to use them. One of them was killed-he snatched a necklace from a kid's neck as he was getting off the train, so the kid shot him in the head. A few weeks later, a guy shot at an MBTA cop as he was running across Mass Ave. Along Huntington Ave. On Comm Ave.