This is a truly fascination story. The swedish inventor Julius Lindblom from Sollentuna outside Stockholm did som very forward looking vehicle experiments in the 1940´s and 50´s using hydraulic suspension in order to get cars to lean when driving into curves. Like a motorcycle.
For this reason Mr Lindblom built a test vehicle partly based on Citroën parts but with a VW flat four engine. The next step was to incorporate the technology in a VW Kleinbus.
The third prototype was obvious the best choice, a Citroën DS. With the DS he could fine tune the system and though he did not used it for road cars Mr Lindbloms ideas and patents was used in the 1980´s high profile fast train in Sweden, the X2000. And yes, the train set is leaning in the curves still today.
Maybe this is not the right place (another section?) but I want to share this amazing footage on Mr Lindblom cars:
http://www.youtube.com/watch?v=KAkmSBhShJI The DS is now being restored to its original shape by a friend of mine, Mikael Thelin.