Dynamic responses of interspersed railway tracks to moving train loads

This paper investigates novel dynamic phenomena of interspersed railway tracks. The interspersed method is commonly carried out by spot-replacing old timber sleepers with new concrete sleepers. Although this interspersed approach provides a short-term solution, such the method has a negative effect on the long-term performance of railway tracks. It is evident that the performance of interspersed tracks can quickly deteriorate after some years. As a result, this paper is the first to evaluate dynamic responses of the interspersed track caused by a moving train load in order to understand the root cause of swift track deterioration. Interspersed track models in three-dimensional space have been developed using a finite element package, STRAND7. The model was validated earlier with experimental results. Parametric studies have been conducted to evaluate dynamic responses of the interspersed railway tracks, including dynamic displacement, frontal uplift, rear uplift and accelerations of rail over sleeper, rail at midspan, sleeper at rail seat and sleeper at midspan. Dynamic amplification phenomena are highlighted as they convey a new insight into dynamic phenomena identifying the real source of track deterioration.