This film shows a few scenes during (almost) late night hours in Downtown Brooklyn along the IRT lines.
The first station is Borough Hall, which is served by (2), (3), (4) and (5) trains. The platforms of the IRT Eastern Parkway Line, which is used by (4) and (5) trains, was the first subway station in Brooklyn, opened in 1908. The platforms of the (2) and (3) trains opened in 1919.
The second station in the film is Nevins Street, which is an express station on the IRT Eastern Parkway Line, still in Downtown Brooklyn. This one is a typical express station with four tracks and two platforms.
For some reason (probably construction), all trains ran exceptionally slow this night.