Simulation models for describing and evaluating the current state (short-term behaviour) and future development (long-term behaviour) of the vehicle/track interaction play a central role in the digitalisation of the railway infrastructure.
These models enable the analysis of how individual system components and their interactions with other subsystems influence the overall system’s short- and long-term behavior. This insight supports the targeted development of products, the design of subsystems, and the derivation of processes.

Additionally, such models provide valuable input for improving and assessing maintenance strategies.

By calibrating and validating the model with historical measurement data, the VTI Model achieves high accuracy. Its physical modeling approach allows it to distinguish between different track sections, it can also distinguish between track sections of different design, such as those with padded sleepers (concrete sleepers coated on the underside with an elastic material) or unpadded sleepers.

Furthermore, the model enables the analysis of additional factors, including vehicle speed, unsprung masses, and rail stiffness.

In this research project, the methodology of this model has been further refined and extended to include the study of ‘hanging sleepers’. Using the Discrete Element Method (DEM)—a computational technique that simulates the movement of large numbers of particles—physical effects at the level of individual gravel particles are analyzed. This approach provides deeper insights into the formation and development of hanging sleepers.

The VTI model will then be extended to provide additional information by incorporating the findings into the existing computationally efficient model landscape.

The models developed are calibrated and validated through extensive laboratory tests and historical field data, and then applied to situations on the railway network. This application covers all track elements – from straight sections to curves and switches. Individual faults and stiffness transitions are also taken into account.

The methodology can be used to produce settlement maps for large sections of track. These analyses provide infrastructure operators with valuable information to make targeted adjustments to the track and thus improve track quality.
In addition, the model allows detailed analysis of the influence of vehicle and operational parameters on the development of vertical and lateral track geometry.

This provides a solid basis for informed decisions on the maintenance and optimisation of the rail network.

After more than three years of research work, the final project meeting took place at VIRTUAL VEHICLE on 2nd October, 2024.

Project partners:

• SBB Infrastruktur
• ÖBB Infrastruktur AG
• voestalpine Railway Systems GmbH
• voestalpine Rail Technology GmbH
• Getzner Werkstoffe GmbH
• Institut für Eisenbahn Infrastrukturdesign, Technische Universität Graz