Sweden’s tilting high-speed train service based on the X2 trainset is called X 2000.
X 2000 is the marketing name used for SJ’s electric high-speed tilting service; X2 is the train’s official technical designation. It was developed for Sweden’s existing railway network, where sharp curves and relatively low population density made building entirely new high-speed lines less practical.
Tilting technology lets the train negotiate curves faster than a conventional train without requiring wholesale reconstruction of the route. The first X2 entered service in 1990, and the trains became especially associated with major routes such as Stockholm–Gothenburg and Stockholm–Malmö.
The other choices are separate Swedish rail services or train families. SJ 3000 is a later high-speed electric multiple unit, Arlanda Express serves Stockholm Arlanda Airport, and Regina is another Swedish train family. They are not the X2-based X 2000 service.