The use of timber sleepers is still indispensable for efficient rail operations. Creosote, which has been used for sleeper impregnation for decades, will probably no longer be available for this application in the future due to European legislation. The research project "Bahnschwelle 2020" was devoted to researching ecologically compatible impregnation products for their suitability for increasing the durability of beech sleepers. One focus was on the transferability of results determined in the laboratory to the beech sleeper. This particularly affected the quality of the impregnation with regard to penetration, impregnation, and active ingredient distribution.