Rolling stock is an asset with a long life cycle which binds a lot of investment capital and brings about high operating costs.A procedure has now been developed which makes it possible to portray i.e. „design” today's long-range effect on the entire life cycle of decisions which must be made today in regard to this investment capital. This „Life Cycle Design” is worked out via a formal system consisting of models and predictions. Its measure is the so-called „Life Cycle Cost”.With the help of the Life Cycle Design various formal solutions can be found for current long-term problems. Based on this an optimal decision can then be made.