First of all, you have to distinguish between a station and a railway stop. There are semaphores at the station, there are not always platforms (e.g. at Gora Włodowska or Psary there are no platforms, and it is a technical station [stth]), but often there are. At the station trains can start and stop, change direction, pass and overtake other trains. The station has at least one main track, which is an extension of the track from an open line, and at least one extra main track, which branches off from the main track.
In the case of a railway stop (marked "po." in the schedule) the indicator "W 16" is set in the braking distance. This is a horizontal rectangle on a white background with three diagonal black bands. This is a signal to the driver that it is time (or about to) start braking if you have a "ph" there.