Pressure variations on a train – Where is the threshold to railway passenger discomfort?

The implementation of recent guidelines for tunnel construction in Germany leads to extended air pressure variations inside trains and reduces pressure comfort for railway passengers. A questionnaire survey with 262 passengers revealed that pressure variations are rated less important for riding comfort than climatic and spatial aspects (study 1). A laboratory experiment (study 2) in the pressure chamber at the DLR Institute of Aerospace Medicine with 31 subjects (mean age = 37.7, SD = 12.7; 51.6% male) investigated the effects of systematic pressure variations on discomfort. The pressure changes (pressure increases and decreases) ranged from 1 to 100 mbar and were realized within 1–100 s. We derived thresholds for healthy passengers by means of random effects linear and logistic regression analysis. Logistic dose–response curves revealed amplitude/time combinations leading to a certain percentage of passengers perceiving discomfort (e.g. 50% dissatisfied passengers regarding a pressure increase of approximately 30 mbar within 5 s). The findings may help design engineers to meet passengers' comfort requirements.

► Recent German guidelines for tunnel construction enhance aerodynamic effects on trains.
► Passenger comfort is currently more determined by climate and space than air pressure.
► We inspect thresholds to aural discomfort for healthy people in a pressure chamber.
► Dose–response curves relate pressure events to percentages of dissatisfied passengers.
► Findings may help design engineers regarding decisions on train and tunnel design.