Experimental and numerical investigations of dual gauge railway track behaviour

[EN] The dual gauge track, in which a third rail is added to the conventional track section, has recently been installed in large sections of the Spanish railway network, allowing the passage of trains of two different track gauges. With increasing train speeds and axle loads, the new dual gauge track must share the main characteristics of current track systems while minimizing the drawbacks, in order to ensure a real step forward in railway track design. Thus, this paper presents a research study on the dynamic behaviour of a dual gauge track generated by the passage of trains. To accomplish this task, an extensive experimen-tal and numerical investigation was conducted in a stretch of the Spanish railway network. The experi-mental work includes the characterization of the rail and sleeper mechanical behaviour during train passage. In addition, results from the experimental investigations were also compared with a fully three-dimensional numerical model. The model uses SOLID95 elements with elastoplastic Mohr- Coulomb behaviour and yields a rMSE of 25% between measured and calculated responses, hence show -ing a good agreement. Concerning the vibrational response, the presence of the third rail have a signifi-cant effect, since the maximum rail vertical accelerations significantly increased on the side where two rails are close together. Finally, the contact pressure between the sleeper and the ballast bed is 35% higher in the common rail when the train runs on the Iberian gauge, but 50% higher on the dedicated rail when the train runs on the standard gauge.