Impact of coupled effects of airtight components at variable cross-section location on vehicle airtightness in Wuhan metro

To determine the variation in airtightness performance of metro trains under the coupling state of airtight components, a field-based experimental approach was employed to test the air pressure changes during metro train operations. The study analyzed the impact of the coupling effects of the air conditioning pressure wave protection valve, pneumatic auxiliary door lock devices, and passageway drainage plug on the interior pressure changes of the train while operating in challenging environmental conditions. Following industry standards, the assessment evaluated whether the rate of interior pressure change and the train’s dynamic sealing index met the specified requirements. The findings indicate that, with airtight components in an enabled state, the peak-to-peak value of interior pressure change relative to external pressure change decreased by 15% to 39%. Conversely, when airtight components were not enabled, the reduction was only 0% to 25%. Under enabled airtight component conditions, the train’s dynamic sealing index was within the 2-3 s range, whereas in the disabled state, the dynamic sealing index was less than 1 s. The activation of airtight components plays a crucial role in improving train airtightness by significantly reducing the amplitude of interior pressure changes, thereby ensuring both train airtightness and passenger comfort. The results provide valuable insights for the optimization of train design and operation in order to maintain passenger safety and comfort.