Tunnels shall be designed such that the maximum pressure variation (difference between the extreme positive and negative pressure peak values, having subtracted the natural pressure variations due to the difference in altitude between the tunnel entry and exit) along an interoperable train shall not exceed 10000 Pascals during the time taken for the train to pass through the tunnel, at the maximum design speed.
Predori so projektirani tako, da maksimalno nihanje tlaka (razlika med skrajnimi najvišjimi vrednostmi pozitivne in negativne obremenitve, po odbitku naravnih nihanj tlaka zaradi razlike v višini med vhodom in izhodom predora) vzdolž interoperabilnega vlaka ne presega 10000 pascalov v času, ki ga vlak potrebuje za prehod skozi predor pri maksimalni predvideni hitrosti.