A General Finite Beam on Tensionless Foundation Model for Rail Track Characterization and Evaluation

Area of Science:

• Civil Engineering
• Geotechnical Engineering
• Railway Engineering

Background:

• Rail infrastructure is vital for mobility, but degraded support leads to track deformation and potential failure.
• Track modulus is a key metric for rail support stiffness, yet current methods oversimplify complex rail-ballast-subgrade interactions.
• Existing models often assume a continuous foundation, failing to account for gap development and spatial variations in track modulus.

Purpose of the Study:

• To develop a general analytical solution for characterizing ballasted track support.
• To accurately model the static response of a finite beam on a tensionless foundation, considering multiple loads and spatial variations.
• To provide a framework for estimating track modulus and analyzing railway track structure health.

Main Methods:

• An iterative algorithm was developed for a finite beam on a tensionless Winkler foundation.
• Singularity functions, superposition of discrete springs, and moment-curvature relationships were used to model complex interactions.
• The model accounts for multiple loads (axle and self-weight), deflection, and spatial variations in track conditions.

Main Results:

• The analytical solution accurately estimates rail deflections, identifies lift-off points, and generates shear and moment diagrams.
• The method was validated against benchmark solutions and previously published results.
• The technique enables the estimation of track modulus from known loads and measured deflections.

Conclusions:

• The proposed method offers a more realistic characterization of ballasted track support compared to traditional approaches.
• It provides a robust framework for analyzing railway track structure and designing sensor data processing for real-time evaluations.
• This work enhances the understanding of rail-foundation interaction, crucial for maintaining safe and efficient rail transport.