The subway maps are great, and I’m glad to see them compiled here, but the statements about the subway history are inaccurate and misleading. Here are just a couple points about it that jump out to me: 1. As others have said, the first subway opened in 1904, and prior to that there were already many elevated lines in Manhattan and Brooklyn. To say that “the subway was in use by 1924” as the first mention of the subway is extremely misleading.
2. In map #16, the green lines do indeed represent the subway, but only the BMT (former BRT) lines. The red lines in this map also represent the subway—the IRT lines. The key on the map even states this.
3. Map #17 and its caption are again extremely misleading. It is true that the subway had expanded by 1926, but it had also already expanded greatly by map #16 in 1924. So again this is a misleading statement. On top of that, map #17 as compared to map #16 does not exhibit further expansion of the subway because firstly it is a map of only the BMT lines (while the prior map showed both BMT and IRT) and secondly every line represented on this map was already shown in map #16.
4. It is true that “by 1971, the subway was huge.” But it was also already huge by 1948, in map #19. The changes that were made to the subway system between 1948 and 1971 were minor and subtle. In fact if you compare the two maps, you will find that there is only one significant addition between the two. You could even argue that the system was more extensive in 1948 than in 1971 because many of the Brooklyn elevated lines and the 3rd Avenue El (black lines on the map) were yet to be torn down. As a lover of the subway and its history, I urge you to do more research on the matter and revise the article to represent it more accurately, because I hate to see it misrepresented here on BuzzFeed.