The Marcus Wallenberg-hallen is a vehicle museum documenting the history of Scania, the Swedish heavy truck and bus manufacturer that has been headquartered in Södertälje since the early 20th century. The collection runs from early 20th-century prototypes to modern production trucks, and includes buses and engines alongside the vehicles. It is well-presented and genuinely interesting even if you are not a truck enthusiast.
Located in the southern part of the city near the Scania production plant. Entry is free. The museum is a good complement to the open-air museum at Torekällberget and the two together make a full day in Södertälje.