a VirtualTourist member
looking 4 train times from amsterdan 2 assen
Direct train leaving from Amsterdam Schiphol Airport at .19 after the whole hours; travel time 2.15 hours.
Non-direct train leaving from Amsterdam Centraal Station at .34 (change trains at Hilversum) or .57 (change trains at Amersfoort) after the whole hours; travel time 2.07 hours.
And for a door-to-door advice see http://www.9292ov.nl/
This site is in Dutch but you can use this tip to help you: [original VT link]
The trip takes a bout 2 hours with a transfer in Amersfoort.