Unsteady Airflows in Rapid Transit Systems

Abstract

The measurement of pressure fluctuations on the London Transport Victoria Line is described and results are presented in sufficient detail for accurate comparisons to be made with theoretical models. Measurements were obtained during the night-time shut-down period, and so complicating effects due to other trains are absent. The results give a clear indication of the relative importance of several events such as entry to and exit from a station. The effectiveness of cross-passages for draught relief is clearly demonstrated. A computer program is used to simulate the airflows, and satisfactory correlation is obtained with the measured results at different train speeds. The program is used to predict system characteristics that were not measured during the tests. It is found that platform wind velocities and passenger pressure histories do not violate recommended acceptable limits even when the train passes through the station at 65 km/h without stopping.