For a while, there has been a bus for the Bergen-Voss section, but the train will restart tomorrow putting Norway in a Nutshell back to regular programming.
Is that a seasonal / winter closure, or was there something else going on?
There had been a freight train derailment near Arna (the first station out of Bergen). Long distance trains were operating Oslo to Voss only, with bus replacements from Voss to Bergen.
The line was closed due to a derailed freight train. More information (in Norwegian) and photos: https://www.banenor.no/nyheter-og-aktuelt/nyheter/2024/arna---vaksdal-apen-for-trafikk-igjen/
The line will be closed again between Voss and Bergen from 0920 on 10 April to 0400 on 16 April due to scheduled engineering work, with rail replacement buses running.
There will be more closures in April as well. Bergen-Arna is being converted from a single track line to a double track line that is scheduled to open 1/5.