Local trains (lines H and C) arrive at and leave the terminus in Frederikssund, and on weekdays there is a 10-minute train service. On Saturdays after 2 pm and on Sundays and Bank Holidays trains to Copenhagen run every 20 minutes. Trains take approx. 50 minutes to reach the main station in Copenhagen.
At Frederikssund station there are bus stops to nearby towns such as Kulhuse, Skibby, Slangerup, Roskilde and Hillerød.
The following link may be useful when you are planning a journey:
Rejseplanen (Journey-planner)
DSB (Danish state railways)
Bus timetables