A subway map expires every night.
At 11:50, two stations joined by a colored line might be twenty minutes apart. After the last train, the line stays on the wall making the same promise, but the route has become a taxi fare, a long walk, or tomorrow. Nothing spatial changed. The geography did.
We treat the schedule as an annotation to the map: a smaller table, a separate app, fine print about service ending. But the schedule is what makes the line real. Tracks are only a possibility. A timed departure turns them into a relationship between places.
I like the last train because it makes infrastructure announce this hidden dimension. The final departure is not just one more vehicle. It closes a door in every station down the line. The city folds inward behind it. When service starts again, the city expands without moving a building.
Maps prefer permanent facts. Rivers, streets, and stations hold still long enough to be printed. Public transit is stranger: its distances are made from waiting, frequency, and the chance to return. Miss the last train and the diagram has not become inaccurate. It has become a picture of a city that is currently unavailable.
The legend should not just name the routes. It should say when this version of the city exists.