Effect of Rail Pad Stiffness on Vehicle–Track Dynamic Interaction Excited by Rail Corrugation in Metro

Abstract

Rail corrugation can cause intense dynamic interaction between train and track, which can reduce riding comfort and lifespan of track structure, and even threaten running safety. Instead of investigating the root cause and growth of corrugation, this case study aims to investigate possible solutions to the excess train–track dynamic interaction excited by rail corrugation in a metro track through both numerical analysis and field experiments. Numerical analysis was performed based on a vehicle–track coupled dynamical model with field-measured rail corrugation information from two curves. The numerical analysis results indicated that rail pad stiffness was the key factor affecting wheel–rail contact force in the studied direct fixation type transit track system. Rail pads with a lower stiffness could reduce the wheel–rail interaction; however, softer rail pads will also increase the rail displacement. Therefore, both the wheel–rail contact force and rail displacement need to be considered while determining the optimal rail pad stiffness. New rail pads with a stiffness of 35 MN/m, which are softer than the original rail pads with a stiffness of 50 MN/m, were recommended for the track in this study. Through field validation and long-term monitoring, new rail pads have been proven to effectively reduce the vehicle–track dynamic interaction and ease the development of rail corrugation to a certain extent. Compared with regular rail grinding, using rail pads with the appropriate stiffness can save transit agencies a tremendous amount of time and cost. The observations from this case study can benefit transit facing rail corrugation problems.

Ray Pedi ve Travers Altı Pedlerin Hat Bileşenleri ve Hat Performansı Üzerindeki Etkileri

“…Bu durumda teker/ray etkileşiminden doğan titreşimler ray pedi ile sönümlenmeye çalışıldığı için ray pedi sistemin oldukça önemli bir parçasıdır. Ray pedi esneme direncindeki değişimler balastsız hattın mekanik tepkileri üzerinde önemli bir rol oynar [8]. Şekil 2(a)'da ray pedinin, W21 ray bağlantı sistemi içerinde kullanımı ve Şekil 2(b)'de kauçuk bir ray pedi örneği gösterilmiştir.…”

“…Teker/ray temas kuvvetleri: Yumuşak ray pedleri teker/ray temasının tahrip edici etkisini azaltır. Song ve diğerleri (2020), yaptıkları nümerik analizde ray pedinin teker/ray temas kuvvetlerini etkileyen en önemli parametre olduğu sonucuna ulaştılar [8]. Hiensch ve diğerleri (2002), Hollanda'da yaptıkları saha deneylerinde sert ray pedlerini yumuşak ray pedleriyle değiştirerek teker/ray etkileşiminin azaldığını gözlemlediler [18].…”

Formation Mechanism of Metro Rail Corrugation Based on Wheel–Rail Stick–Slip Behaviors

“…Therefore, it is more convincing to study the microscopic wheel-rail contact behaviors to reveal the formation mechanism of rail corrugation. For metro lines, rail corrugation mostly occurs in the small radius curve sections, and the corrugation of the inner rail is more serious than that of outer rail [29,30]. Meantime, abnormal rail corrugation with a short recurrence period also occurs in some large radius curves and straight sections [31][32][33].…”

Development characteristics of corrugation at different passing speeds

“…Liu et al [20] brought forward a cause theory of rail corrugation of friction induced torsional vibration, and explained that most of the corrugations occurred on the inner rail. By numerical analysis and field test, Song et al [21] discussed the solution to the excessive dynamic effect of vehicle-track system caused by rail corrugation. Ma et al [22] revealed the mechanism of corrugation according to the corrugation growth rate.…”