Impact of Rail Dampers on the Mainline Rail Roughness Development

To investigate the rail damper influence on the long-term development of rail roughness, a frequent measurement schedule was executed at an Austrian mainline. To get representative results also for further networks a common used track type was chosen, consisting of concrete sleepers with sleeper pads, 60E1 rail profile and soft rail pads. The latter allows a relative high noise emission of the rail. One track section was measured where the rail dampers of Schrey & Veit GmbH are installed, an adjacent track section serves as reference section (without rail dampers). The ‘natural’ roughness of this track section is low but differs at one of the four sections. Due to conventional rail grinding and the subsequent train operation, all roughness levels become similar after about three months. The following and two-monthly repeated measurements show the slight increase and a ‘tonal’ peak which disappears after 2–6 months. After a 13 month interval no further changes are visible. The overall results are showing low and widely similar rail roughness values for both sections at both rails. For this track/vehicle/rail damper constellation, the rail dampers are no obstacle to reach again the very low rail roughness levels. Although differing in many parameters, further measurement results (mainline and metro network) are leading to related results. Additional investigation of the mechanical interactions of the system vehicle—rail—rail damper is needed, to tune the dampers for an increased effect on roughness development, especially in curves.