The InfraMag trains have a speed of 450 km/h  and in the times indicated, it includes start and brake times and a 2 minute break per station. There is also a time indicated for a direct line.

Compilation Stockholm - Oslo

It must be said at once that there are several alternative routes to draw traffic to Oslo. What will later determine the draw, we leave in this account, but refer to a proposal. 

Tider med Tesla bil och med flyg

Driving to Oslo from Stockholm is not efficient
alternative. Takes a full 7 hours and 8 minutes.

To fly with the electric powered aircraft available
is also not an option. They have to stop over to charge
the batteries, or replace the batteries. Takes 3 hours and 20 minutes.

On the other hand, if you take a direct train to Oslo, it takes 1 hour and
11 minutes and you can use the time for work to 100%.

Result: The train is the only real option.

Note: The flight has today only presented flights with a performance of
50 passengers and a range of 250 km and at a flying speed
at 500 km/h.