The Complicated History Behind New York City's Missing Subway Lines

A recent article on Quartz discusses the detailed and complicated history behind New York City's missing subway letters.

At first glance, there is logic to New York City’s numbered subway lines: 1, 2, 3, 4, 5, 6, 7. The letters, however, are a little less straightforward: A, B, C, D, E, F, G, J, L, M, N, Q, R, S, S, Z. What happened to the H? Or the O? And why in the world there are three S trains—shuttles going between Grand Central and Times Square in Manhattan, between Prospect Park and Franklin Avenue in Brooklyn, and to Rockaway Park—when there could easily be an S and, say, a K? To understand how this came to be, we need to go back 111 years, when the subway opened in Manhattan on Oct. 27, 1904.

Check out the full article for a fascinating read on the case of the missing subway letters and New York City transit history.