Subway Stations - mattyschell/nyc-spatial-rolodex GitHub Wiki
Open Data Portal
This appears to be extracted from the Department of Information Technology and Telecommunications (DoITT) Street Centerline (CSCL) database.
https://data.cityofnewyork.us/Transportation/Subway-Stations/arq3-7z49
At times this download has included both closed and future (planned) stations. Probably best to verify what you get today if these sorts of details matter to you.
Intuitively you would expect that a subway station corresponds to one or more Subway-Lines and Subway-Entrances. If you have downloaded other "subway" datasets that include the Staten Island Railway, best to check that the download here matches the other ones, if that sort of detail matters to you.
Metropolitan Transportation Authority
http://web.mta.info/developers/developer-data-terms.html
Click down at the end to accept the terms and good luck. Data feeds are in General Transit Feed Specification (GTFS) format. https://developers.google.com/transit/gtfs/