How many sound stages were used to build the train set?

The verified evidence from Wikipedia focuses on the plot summary, cast, and production details of How to Train Your Dragon 2 as a DreamWorks Animation film. It describes the story following 20-year-old Hiccup and his friends as they encounter Valka and Drago Bludvist. However, the evidence does not include any technical production details about sound stages or train set construction for the film. Without access to additional sources that document the film's physical production facilities, I cannot provide a definitive answer about the number of sound stages used.