- Delémont - Biel - Neuchatel - Yverdon - GVA
The 1976 movie "The Cassandra Crossing" was filmed for quite a part on that route. First, the gentle hills between Basel and Delémont for some 40 km...
...then the railway cuts through several gorges...
and then aligns itself with two lakes, Lake Biel and Lake Neuchatel for about an hour.
Then, between Yverdon and Lausanne, you see the Jura hills on the one side and the northern Alps on the other. Between them, magnificient views of pastures. And at each larger city on that route, I recommend visiting the old town or the lake shore. Intercity trains run every hour.
And the best thing is: Despite it good views, it isn't a tourist-infested route!
Keeping calm is terrorism against those who want to live in fear.