High-speed trains experience strong fluctuations in ambient pressure during tunnel passages and oncoming traffic, which can reach up to ±10,000 Pa. These pressure surges would enter the interior of pressure-resistant rail vehicles through the fresh air and exhaust air ducts of the air conditioning systems. When pressure differences occur inside the vehicle, this leads to very unpleasant pressure sensations in people’s ears. Pressure protection systems consist of a pneumatically operated pressure-tight closure and an electronic differential pressure measurement, which detects the pressure fluctuation and sends the signal to the pneumatics to close the mechanism when limit values are exceeded.