Local transit historian and railfan Dj Hammers makes tons of great videos showing how subway transit works and runs in the City.
In this great 10 minute time lapse video, see what the J train sees as it runs its route through Manhattan and Brooklyn.
The J is a rapid transit service in the B Division of the New York City Subway. The J operates at all times and uses the entire BMT Archer Avenue, Jamaica, and Nassau Street lines between Jamaica Center – Parsons/Archer in Jamaica, Queens and Broad Street in Lower Manhattan (via the Williamsburg Bridge between Brooklyn and Manhattan). On weekdays, trains run express in the peak direction in Brooklyn between Myrtle Avenue and Marcy Avenue, bypassing three stations.