Impact of Frog Height Deviations on Dynamic Response of High‐Speed Metro Trains Negotiating Turnouts

Composite frogs inevitably have manufacturing or installation errors, leading to deviations in the height of the frogs, which affects the dynamic performance of trains passing through turnouts. This study focuses on high‐speed metro systems operating at 100 km/h or higher. Based on field‐measured No. 12 composite steel frog contours and metro LM wheel profiles, a coupled vehicle‐turnout dynamic model is established to analyze wheel–rail contact characteristics and dynamic responses when trains pass through frogs in reverse. The findings reveal that excessive deviations in the height of the frogs can significantly degrade the dynamic performance of trains passing through turnouts. To ensure operational safety, stability, and passenger comfort, it is recommended to maintain deviations in frogs’ height within the range of −2 mm to +1 mm. From an operational and maintenance perspective, corrective measures should be implemented when the frogs deviate beyond the specified limits.