Characterization of forces, dynamic response, and sound radiation from an articulated switch sleeper in a turnout system

Abstract

Pre-assembled turnouts have recently been introduced with split concrete sleepers joined by elastic coupling plates. Their effect on the forces, vibration response, and sound radiation as trains run through a turnout is studied here using a calculation model for a whole turnout based on the finite-element method. The non-linear characteristics of the ballast's support under the sleepers, as well as the special construction of the articulated joints, are included. It is shown that compared with the normal integral sleeper design, the track with articulated switch sleepers has a lower rigidity, which changes more evenly along the track and improves its dynamic performance. Furthermore, the fatigue strength of an articulated switch sleeper is higher due to its lower stress amplitudes. Additionally, when the vehicles are running on the main turnout route, as the switch sleepers’ vibration behaviour is modified, the articulated joints effectively reduce the impact loading of the ballast at the end of the sleeper under the turnout branch track. This will extend the life of the ballast bed. Finally, the sound radiation from the articulated switch sleeper is very low in the hinged short part and is reduced by about 0.6 dB for the total length.