SJ is the primary passenger train operator in Sweden. A wholly state-owned company operated for-profit under market conditions, SJ operates various services across Sweden. SJ's operations include high-speed trains, intercity trains, night trains, and regional trains, with some services extending into Denmark, Norway. and Germany. SJ traces its roots back to 1856, however was established in its current form as a passenger train operator (SJ AB) in 2001, following the restructuring of Statens Järnvägar, the former government agency responsible for the Swedish railways.
https://en.wikipedia.org/wiki/SJ_AB