The X3 is a member of the Alstom Coradia family that was designed to provide high speed service between Stockholm central station and Arlanda airport. Each set consists of four cars, of which the outer two are being powered on each axle by a 280 kW traction motor. They are designed for a top speed of 205 km/h and are being operated with 200 km/h. Both stations have higher platforms to create a level entry. Seven sets were built in 1998 and 1999 at Birmingham and now they are only used for the Arlanda Express. After some refurbishments in the interior, they are to be replaced around 2030. 