X 2000, also called SJ X2 or simply X2, is an electric high-speed tilting train operated by SJ in Sweden. It was constructed by Kalmar Verkstad in Kalmar, Sweden and launched in 1990 as a first-class only train with a meal included in the ticket price, and free use of the train's fax machine. There is a bistro on board that serves snack bar-style dishes. From 1995 second class was introduced. All trains are equipped with Wi-Fi for passenger access to the Internet and were repainted grey as of 2005. The trains also have electric power supply sockets at all seats in both first and second class. The trains have been fitted with repeaters to improve mobile phone reception.

A tilting train is a train that has a mechanism enabling increased speed on regular rail tracks. As a train rounds a curve at speed, objects inside the train experience centrifugal force. This can cause packages to slide about or seated passengers to feel squashed by the outboard armrest, and standing passengers to lose their balance, or in such excessive speeds, could even cause the train to derail. Tilting trains are designed to counteract this by tilting the carriages towards the inside of the curve, thus compensating for the g-force. The train may be constructed such that inertial forces cause the tilting, or it may have a computer-controlled powered mechanism.