Berlin Maastricht Bahn. Deutsche bahn (db) is the main provider of train services in germany, making on average 40, 000 journeys per day. The man in seat 61.
Alternatively, you can take a bus from maastricht to poznań via venlo station and venlo in around 12h 40m. Or from berlin by direct ic train right into the west to amsterdam. You can compare the best prices from all train lines and book online directly with wanderu.