At the northern tip of the Netherlands' intercity network, Groningen is well-connected to the rest of the country, with intercity trains heading south every 30 minutes. Timetable information can be found at the railways' site www.ns.nl or at the general public transport site www.9292.nl. Amsterdam central station can be reached in just over 2 hours, with a change at Amersfoort or Lelystad. There are direct trains to Amsterdam Schiphol Airport and The Hague, and to Rotterdam.
Tickets can be bought from the machines at the station, online at www.ns.nl (for printing at home) or (at an extra fee of €0,50) at the station ticket counters. If you're using an OV-Chipkaart you just need to 'check in' using one of the terminals on the platform before boarding the train; remember to 'check out' at your final destination. Dutch trains do not have reserved seats, and your ticket is valid all day in any train going as directly as possible to your final destination.