SJ X40

The X40 is a series of electric multiple units operated by SJ, the primary passenger train operator in Sweden. They are in service from Stockholm to Linköping, Västerås/Örebro, Uppsala and Gävle/Sandviken, and since 2010 to Gothenburg via Västerås. The double decker trains were built by Alstom from 2004 to 2008, with 43 units being delivered, either in a two-car or three-car configuration. It is based on the Coradia series, very similar to the French SNCF Class Z 26500 double decker trains, and similar to the X60-series. The X40 is the first true double-decker train to operate in Sweden, although the first and last cars of the Y3 were built in a style similar to dome cars, connected to single-deck coaches. From 2019 onwards, the bilevel Stadler KISS (known as DOSTO in Sweden) has also been used in the Mälardalen and Uppsala regions of Sweden, and since 2023, Tåg i Bergslagen has operated the same train sets in the Bergslagen region. Among crew and technical support the vehicle early got nicknamed "Flodhäst", in English "Hippo - big, gray and unpredictable". The X40 is currently being refurbished which will modernise the double-deckers so that they can last for about 15 more years.