We are wanting to take a night train from Oslo to Bergen in a few nights. We are in Denmark now so since it’s intracountry in Norway they can’t do reservation for us. How can we book reservation online with using our eurail passes?
Do you have a smart phone? You can download the Norwegian Rail App and make a reservation with it.
Otherwise at Rail Europe.
Rail Europe doesn't have e-ticketing for the Norwegian railway and I'm not sure whether NSB will both sell sleeper-only reservations and take US credit cards reliably online. It's probably easier to call NSB: (47) 81-50-08-88 (press 9 for English).