There currently is one option to travel by night train from Bergen (Norway) to Oslo (Norway), taking approximately 7 hours: Namely the 606 operated by VY.
VY is Norway's railway company and operates night trains across Norway. Currently, the company operates a route between Oslo and Bergen.
Sleeper compartments are booked as a whole and provide two beds with quality mattresses, bedding and personal care facilities. Children under six travel free, and children over four are recommended to have their own berth. Wake-up calls are made before arrival.
Couchette compartments provide sheets, pillows and blankets which passengers arrange themselves. Each berth includes a reading light, wall storage and USB port. Compartments have two power sockets. Middle and upper berths have fixed safety rails, and ladders are available. Berth sizes vary and are narrower than standard mattresses.
In addition to sleeper and couchette options, VY provides premium flat-bed seats with privacy from the aisle. Second class seating reclines partially and includes a night package with sleep accessories.
Breakfast is not provided on board. However, VY has partnerships with hotels in Oslo and Bergen offering discounted breakfast packages for night train passengers.