The Swiss Federal Railways (SFR) use glyphosate as the only herbicide for the chemical weed control on railway tracks. After the application on the railroad embankment the herbicide can be partly transported with the rainfall to the aquatic environment. In order to assess the potential environmental pollution glyphosate and its main degradation product aminomethylphosphonic acid (AMPA) were analysed in selected drainage water of the railroad embankment from all over the railway system. The results were compared with studies in other European countries. Furthermore, the time-dependent concentration dynamics during one rain event was investigated at one selected sampling site.