Recently I posted that there seemed to be no room left in the subway tunnels and bridges leading into Manhattan. Threestationsquare, who had made the updated chart I used in that post, pointed me to the New York Metropolitan Transportation Council's Hub Bound Travel Study. And it turns out I was wrong. There is room - and the places where there is room have interesting potential.
The NYMTC is an arm of the New York State Department of Transportation that is responsible, among other things, for coming up with wildly inaccurate predictions of traffic volumes to justify bigger highways. But their underlying data is more sound, and a lot of it is online. The Hub Bound Travel Study is full of fascinating data for transportation nerds, and I wholeheartedly recommend it.
For our purposes, the relevant table is Appendix I, Table 6, "TOTAL RAIL TRAINS ENTERING AND LEAVING THE HUB ON A FALL BUSINESS DAY." Kind of poetic. (But it's trains going to the hub, not The Hub). If we look at the morning rush data for 2012, here's what we get:
There's a pretty wide spread between the #7 train, which manages to cram 23 trains per hour through the Steinway Tunnel, and the R train, which only sent eight trains an hour through the Montague Street Tunnel. In between we can see clusters in the low 20s, in the mid-teens, in the low teens, and then a few stragglers.
The busiest tunnels are the Lexington Avenue Express, the PATH, and the 60th and 53rd Street Tunnels to Queens. The uptown Broadway Express and the Cranberry Street Tunnel are also doing pretty well.
There is significant room on the Manhattan Bridge (as Threestationsquare mentioned) and the uptown #6 Local and Central Park West Express, and the Clark Street Tunnel to Brooklyn. Even the 14th Street Tunnel has capacity, despite promises that CBTC would improve things. We knew the Williamsburg Bridge had capacity, but it turns out, so do the locals on the Upper West Side.
The Montague Tunnel is currently closed to repair damage from Hurricane Sandy, but it's seen eight trains an hour since the M train was rerouted uptown in 2010. They ran 27 trains per hour in 2002, before the N was rerouted over the Manhattan Bridge. The R is just not a high-demand train in this area, because it crawls through Lower Manhattan. The two tunnels for the F (Rutgers Street and 63rd Street) see more trains, but they have plenty of room.
So there you have it! Looking forward to your fantasy maps...