The importance of ‘dynamics’ in the design and performance-based testing criteria for railway track components

It is unquestionable that track dynamics have caused various problems in railway operations and maintenance. Broken sleepers due to impacts at rail joints, switches and crossings, transition zones, bridge ends, and so on can result in failure of fastening systems and later lead to detrimental train derailments. Excessive ballast settlement and dilation from dynamic load conditions can weaken track lateral resistance and eventually track misalignment under extreme climate. These are a couple of clear evidences that railway industry faces daily. However, most railway practitioners still ignore the dynamics aspects when designing, testing, and manufacturing railway track components. The importance of ‘dynamics’ in the design, performance testing and manufacturing of track components have been highlighted with evidences in this paper. The thorough review of track load conditions is discussed. The proposed change from static or quasi-static design to a more rationale dynamic design has been discussed. This implies the change from “quasi-static load > static analysis and design > static and cyclic tests > quasi-static behaviors > individual component performance” to “realistic dynamic load > dynamic analysis > dynamic design and behavior > individual component performance > track performance”. Fundamental issues of dynamic testing of materials and structural components have been described to aid the understanding of inexperienced practitioners. The essential need to determine dynamic properties of materials and components, for dynamic design considerations will be highlighted. It is crucially important that such the dynamics aspects are highlighted so that the dynamic resistance of the components and railway tracks can be established for better public safety and operational reliability.