Reassessing Eurocode’s Passenger Comfort Criteria in Railway Bridges

The vertical deflection limits currently adopted in European railway bridge design to ensure passenger comfort originate from the ERRI D160 and D190 studies. These studies established a link between static deck deflection and simplified comfort vehicle response indicators, reflecting the scope and comfort modelling practice of that period, forming the basis of the criteria later incorporated into EN 1990, Annex A2. EN 12299, in turn, defines passenger comfort indices based on objective representations of how the human body responds to vibration and perceives comfort. However, it was conceived for long-track sections, which limits its direct applicability to punctual bridge crossings. This study revisits deflection-based comfort by combining (i) conventional L/δ verification under LM71 with a dynamic amplification factor and (ii) TTBI simulations used as supporting evidence on parametric bridge models informed by an extensive dataset of real European bridges, spanning wide ranges of span, stiffness and typology. The parametric set enables systematic coverage of common structural forms (e.g., supported and continuous decks) and representative stiffness and mass levels. Particular attention is given to the short-duration, spatially localized excitation during crossings and to the influence of speed. Correlations between deflection indicators and EN 12299 Mean and Continuous Comfort measures are quantified, and sensitivity to bridge typology and train speed is examined. The work proposes a revised assessment framework that retains the simplicity of current deflection checks while grounding them in TTBI evidence and EN 12299 aligned comfort metrics.