Interference effect of three moving trains on the response of a ballasted railway track

This paper presents a comprehensive investigation into the interference effects of three moving trains on railway tracks using three-dimensional (3D) finite element analysis. The primary focus is on understanding the behavior of the middle train and its settlement characteristics when influenced by two neighboring moving trains. To establish a baseline, the study also includes an analysis of a single train. The train speeds considered in the analyses range from 100km/h to 450km/h, and the spacing between trains (S) varies across 10 values from 1m to 10m. The results reveal intriguing patterns in the settlement behavior of the middle railway track. Specifically, the interface significantly impacts settlement, causing a decrease for S = 1m compared to a single railway track and a subsequent remarkable increase for larger S values. This conflicting behavior arises from the combined effects of confinement and vibration induced by neighboring trains. Moreover, as the spacing between trains increases, the interference effect diminishes due to a decrease in vibration. Quantitative findings include an average percentage difference in the maximum settlement ranging from -16% to +109%, with the interference effect decreasing as S increases. The critical speed of the middle train's railway track is also influenced by interference, exhibiting a change from 300km/h to 350km/h for S values of 2-6m. This highlights the necessity for special attention to interference effects in the design stage, particularly regarding critical speed considerations. The study contributes valuable insights into the complex dynamics of three moving trains on railway tracks, offering practical implications for railway track design and ensuring safe and efficient operations.