You may have noticed, in riding the subways of New York, that the MTA has posted a clear warning in every car. Why so many reminders? Is it because of the incessant delays? The changing of an express to a local, a C to the F Track, without an announcement? Or is it perhaps the conductors’ proclivity toward closing the doors just as the other train arrives on the other side of the platform?Whatever it is, seven years is a long time to wait.