You may go by vybus from Göteborg. Arrives Oslo the sane day at 22.40. (Train from Copenhagen to Göteborg at 14.27)

There are lots of construction works on the Norwegian railway around Oslo which affects the trains.

The old time directs on to K/obenhavn have been split in Göteborg as O/resundttag now runs hourly direct. From there north its VY (ex NSB), nice trainset, but only ev 4 hrs-and when I took it last week less as half full-no RES even needed. This VY is NOT in the app-but of course on its own site and sj.se.

As anna-fra Sverige explains- long time Banearbeter=works have been in force nearly all summer along this route-and all the lines are single track, so then its bussen. Fra KÖpenhamn you can go certainly till Göteborg-about 4 hrs. Ditto on the line east fro Olso going on to Karlstad-and STO. Distances are just a bit too long for using trains for bisnispeople, enough flights, but no real cheapees, so the buss now takes the brunt of budget travellers-and they are even faster too and also run overnight.

Besides FLIX (often quite unreliable in timekeeping) there is indeed also VYBussen (or perhaps often under its old name-Nor-way Ekspressen), in Gb the big (and half deserted now) BUSS stasjonen is right beside Toget-stasjonen.

All over in Scandinavia labour is extremely sparse-well paid if you like-and this makes utmost economies. I stayed in GB last week in what is there a budget HTL and did not see anyone in real life till next morning at BF_and payment. All stasjoner close for a few hrs nighttime-to keep the homeless out.

Norway has a very difficult geography in comparison to Sweden and Finland, and therefore not a lot of border-crossing railways. A lot is single track indeed, which means an incident or engineering works can screw it up a lot indeed.

If you time it well, what could save you a bit more time (but also not more then 30 minutes) is to take the train from Copenhagen to Helsingor, take the ferry to Helsingborg. Superb connection with both station, costs only 7 euro’s for foot passengers. Ferries are every half hour and only take 20 min.

From Helsingborg there’s also relatively frequent (at least more than the trains) direct busses to Oslo. Bit it also takes about 7-8 h to get from  Copenhagen to Olso via Helsingor-Helsingborg.

If you’re lucky, you can see the working heritage steam-trains in Helsingor. :)