Nutshell: which side of the train is better?

Right side in the low lands to Honefoss. Left side when train turns west and ascends Hardangervidda.

http://en.m.wikipedia.org/wiki/Bergen_Line

Leaving Oslo S, the first section goes through urban areas and tunnels. From around Drummen to Honefoss the track follows a river and waterway ( don't know its name) with the water on the right and steep banks/slopes on the left.

From about Honefoss, the route turns towards Bergen and starts a long climb to the Hardangervidda. During the snow months the skiers and view are on the left when traveling eastward.

Thanks, Edgar.

I found the other side is always more scenic. But actually, get a seat on the left if you are going from Oslo to Flam...especially from Myrdal to Flam. And in fact I think the left was the best side for the entire Nutshell trip from Oslo to the fjords to Bergen.

It depends on how attractive the other passengers are, but the outside is usually more scenic. : > )