An efficient physical-based method for predicting the long-term evolution of vertical railway track geometries

Abstract

The dynamic wheel-rail contact forces resulting from the interaction between vehicle and track are responsible for the local track settlement. If these local settlements vary along the track, geometric irregularities develop further amplifying the dynamic loading of the track caused by the interaction between the vehicle and track. In this work, an efficient vehicle-track interaction (VTI) model is presented for predicting the long-term evolution of vertical track settlement during operation. The VTI model has two interacting components – vehicle and track. The vehicle model describes the vertical dynamics of an 8th of a car. The track model considers an elastic rail on discrete (sleeper) supports. Each sleeper location can have its own stiffness, relative height and settlement characteristics. Dependent on the distribution of stiffness and settlement behaviour along the track together with the initial track geometry, each sleeper settles dependent on the number of load cycles (vehicle passes). The track model is initialized with measured vertical track geometry data and static track deflection data at the beginning (day 0) for two types of track sections in the field, a track section where concrete sleepers with Under Sleeper Pads (USP) are used and a track section where only concrete sleepers are used. Using the same settlement model parameters (constant along the track) for the two tracks, the physical-based VTI model can predict the different track geometry quality evolution for both tracks over 350 days. Finally, the VTI model is used to assess the track geometry deterioration when the track/vehicle properties are changed. The prediction strength of the fast VTI model based on the physical understanding can assist in designing and optimizing tracks and in supporting of maintenance activities.

Using Detailing Concept to Assess Railway Functional Safety

“…The risk assessment of the functional safety [42][43][44][45][46] of any engineering object is associated with the definition of reliability [47][48][49], availability, maintainability, and safety (RAMS) [50,51]. It determines the suitability of objects to perform their functions safely (with defined risk levels at all stages of the life cycle) [25,52,53] and efficiently (with a certain level of costs) under specific operating conditions [54][55][56][57]. This state is assessed by deformability.…”

Modelling railway track differential settlement for prediction of future deterioration and maintenance intervals

“…To address the aforementioned challenges, methodologies to predict differential track settlement without relying on historical track geometry records and consider the evolution of track geometry irregularities has been studied by [4]- [7]. However, it is challenging and computationally demanding to calculate the distributions of 3D dynamic stresses in the track and the ground when modelling over a larger number of cyclic loads in the time domain, particularly for large track structures [8]- [10].…”