SJ_X40
The X40 is a series of electric multiple units operated by SJ of 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 2004–2008, 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 DOSTO will also be used in the Mälardalen and Uppsala regions of Sweden.
Among crew and technical support the vehicle early got nicknamed "Flodhäst", in English "Hippo - big, gray and unpredictable".