Vehicle, Mobility and Transportation Design Deutsche Bahn Add-ons Train Improvement Concept by Gerhardt Kellermann With Add-ons the munich based Studio RELVAOKELLERMANN presents an economic approach for the upgrade and modernization of existing trains. The concepts of Add-ons consists of individual elements. They are build onto trains or their interior. Due to a long life period of existing trains, they offer targeted solutions without large or new developments. The Add-Ons can act quickly and simple to the rapid development in passenger transport and their problems and requirements. The work is limited to three examples for three observations.