Passenger comfort visualized assessment in high-speed railway tunnels using functional near-infrared spectroscopy (fNIRS) brain imaging technology: A full-scale test study

• fNIRS provides objective neurophysiological measures of passenger comfort in high-speed railway tunnels, quantifying subjective experiences. • Tunnel passage and sonic booms significantly increase temporal lobe HbO levels (87% and 175% respectively), indicating transient discomfort. • Brain functional connectivity enhances by 52% during tunnel entrance and 80% during sonic booms, reflecting neural responses to environmental stressors. • The study establishes a foundation for evidence-based comfort optimization in railway design using real-time brain imaging.