All the train cars are color coded neat, orderly, organized, thought out and boring. The lives of the cars lack excitement, carting ungrateful impatient people around all day is just no fun.
The Color Coded Train Cars disengage from their tracks, its time to do something. This is when the Green line learns that it is not designed for platforms, it can't see over the edge and its stairs start much too low. The Red line loves that nobody can board at Brookline Village, Chestnut Hill and all the rest. The people just can't reach, and the Blue line never makes it to Wonderland.
The City is confused, the City is frightened, the City is Late. The City scolds the Color Coded Train Cars for their mischief, and the cars themselves are left unfulfilled.