The concept of the rail damage function provides vital understanding of the operational performance of rail grades in terms of surface degradation. Previously, material specific damage functions have been derived from measurements in track combined with vehicle-track simulations. However, from the occurring wide range in track loading conditions it is difficult to achieve clear characterisation results from track data only. To reach more controlled loading conditions, a rolling-sliding two-disc laboratory set up could be applied. The validation of a two-disc test approach in order to define rail/wheel interface wear and RCF response is the topic of the here presented study.

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The extensive usage of railway infrastructure demands a high level of robustness, which can be achieved partly by considering (and managing) the track and rolling stock as one integral system with due attention to their interface. A growing number of infra managers consider, in this framework, the track-friendliness of vehicles that have access to their tracks as a key control parameter. The aim of this study is to provide further insight into potential contributions to track-friendliness, assessed in relation to track deterioration mechanisms and cost, understanding how potential benefits are best to be utilised. Six proposed freight bogie design measures are evaluated with respect to the improvement in curving behaviour, switch negotiation and related track degradation mechanisms. To this purpose a sensitivity analysis has been carried out by means of track–train simulations in the VAMPIRE® multi body simulation software. Additionally, the impact on track deterioration costs has been calculated for those track-friendly design modifications identified as most promising. Conclusions show that the standard Y25L freight bogie design displays rather a track-friendly behaviour. Tuning the primary yaw stiffness shows a high potential to further improve track-friendliness, significantly reducing track deterioration cost at narrow radius curves and switches (by, respectively, 30% and 60%). When calculating the overall deterioration cost for the travelled route, the calculation model should include a well-balanced representation of switches and narrow radius curves.

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The concept of the rail damage function provides vital understanding of the operational performance of rail grades in terms of surface degradation. The present study extends this concept from conventional to premium pearlitic rail. This is done on the basis of both simulations of dynamic train-track interaction and field observations. Rolling Contact Fatigue (RCF) damage index values for the conventional R260Mn and the premium R370CrHT grade rail are established, describing the behaviour of the associated damage functions. Defining the individual rail grade damage response to operational loading levels, the potential of the RCF-damage function to support the process of rail grade selection and track maintenance is further discussed.

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The concept of the rail damage function provides vital understanding of the operational performance of rail grades in terms of surface degradation. Previously, material specific damage functions have been derived from measurements in track combined with vehicle-track simulations. However, from the occurring wide range in track loading conditions it is difficult to achieve clear characterization results from track data only. To reach more controlled loading conditions, a rollingsliding two-disc laboratory set up could be applied. The validation of a two-disc test approach in order to define rail/wheel interface wear and RCF response is the topic of the here proposed study.@en

The acting forces and resulting material degradation at the running surfaces of wheels and rail are determined by vehicle, track, interface and operational characteristics. To effectively manage the experienced wear, plastic deformation and crack development at wheels and rail, the interaction between vehicle and track demands a system approach both in maintenance and in design. This requires insight into the impact of train operational parameters on rail- and wheel degradation, in particular at switches and crossings due to the complex dynamic behaviour of a railway vehicle at a turnout. A parametric study was carried out by means of vehicle-track simulations within the VAMPIRE® multibody simulation software, performing a sensitivity analysis regarding operational factors and their impact on expected switch panel wear loading. Additionally, theoretical concepts were cross-checked with operational practices by means of a case study in response to a dramatic change in lateral rail wear development at specific switches in Dutch track. Data from train operation, track maintenance and track inspection were analysed, providing further insight into the operational dependencies. From the simulations performed in this study, it was found that switch rail lateral wear loading at the diverging route of a 1:9 type turnout is significantly influenced by the level of wheel–rail friction and to a lesser extent by the direction of travel (facing or trailing). The influence of other investigated parameters, being vehicle speed, traction, gauge widening and track layout is found to be small. Findings from the case study further confirm the simulation outcome. This research clearly demonstrates the contribution flange lubrication can have in preventing abnormal lateral wear at locations where the wheel–rail interface is heavily loaded.

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In this paper the performance of primary suspension elements with Frequency Selective Stiffness (FSS) behaviour in bogies is presented with respect to the ability to reduce wear and fatigue damage at the wheel-rail interface, thus enhancing the so-called 'track friendliness' of trains. Vehicle behaviour during negotiation of a turnout is evaluated in a case study with the Dutch double stock VIRM-4 train. Assessment of vehicle running behaviour is carried out by means of track-train simulations within the VAMPIRE multibody simulation software. The impact of FSS suspension elements is quantified in relation to wear and rolling contact fatigue damage (RCF) in the wheel-rail interface and regarding ride quality. The research shows that with application of FSS elements at the primary suspension, wear loading of switch and closure rail can be reduced significantly, increasing expected maintenance intervals and rail life. Simulation results demonstrate passenger comfort levels not to be influenced negatively.@en