Refined nonlinear fractional derivative model of vehicle-track coupling dynamics

The coupled vehicle-track system (CVTS) dynamics have been extensively investigated for decades. However, the calculation accuracy of prevailing vehicle-track coupling models needs to be improved in the high frequency range due to the inappropriate model simplification and neglect of material nonlinearity. In this study, we propose a refined...

Numerical investigation of the behavior of stone ballast mixed by steel slag in ballasted railway track

Recently, implementing steel slag ballast has been proposed as an appropriate material to substitute stone ballast. In this regard, one of the technical concerns is the behavior of steel slag ballast in both time and frequency domains that needs to be assessed, properly. Furthermore, the combination of stone ballast and steel slag is...

Numerical investigation of rubber swelling in bitumen

Crumb rubber modified bitumen (CRMB) has been utilized in the asphalt paving industry for decades due to its various benefits. The main mechanisms of bitumen-crumb rubber interaction include rubber particle swelling and chemical degradation. Crumb rubber modifier (CRM) swelling plays a dominant role in controlling the property development of...

Corrective countermeasure for track transition zones in railways: Adjustable fastener

Transition zones in railway tracks are the locations with considerable variation in the vertical stiffness of supporting structures. Typically, they are located near engineering structures, such as bridges, culverts, tunnels and level crossings. In such locations, the variation of the vertical stiffness and the differential track settlement...