A few months ago, I was on the B line going inbound. When the train got to Packard's Corner, the driver announced that the train would be going express to Kenmore. When the train got to Babcock Street, it stopped and the second car opened it's front door to let people on. Then again at Pleasant Street, the train stopped and the second car opened it's door to let people on.
At St. Paul Street, the train stopped again, and once again the driver of the second car opened the door to let people on, and then the driver came over the intercom, "Close your door, we were express." The train stopped at all the rest of the stops before Kenmore with the driver on the intercom yelling, "We were express, close it up, you keep holding me up, they keep calling me, evidently your radio doesn't work!" And the entire time the conductor of the second car very calmly opened his door and wouldn't close it until everybody was on. That was the slowest express train I've ever been on.