Also see: - https://bernardgreenberg.com/Subway/ https://bernardgreenberg.com/Subway/ - https://github.com/BernardGreenberg/NXSYS https://github.com/BernardGr

Also see: - https://bernardgreenberg.com/Subway/ https://bernardgreenberg.com/Subway/ - https://github.com/BernardGreenberg/NXSYS https://github.com/BernardGreenberg/NXSYS - and the incredible pages on the nycsubway.org site such as https://www.nycsubway.org/wiki/Subway_Signals:_A_Complete_Guide https://www.nycsubway.org/wiki/Subway_Signals:_A_Complete_Gu... - and https://bernardgreenberg.com/Subway/bsg-subway.html https://bernardgreenberg.com/Subway/bsg-subway.html