Objective In mixed-formation coupled operation, if a train fails, rescue schemes designed for single-formation modes cannot be fully applied. To ensure line service quality, it is necessary to timely adjust train timetables and select reasonable train rescue schemes.

Method To address issues such as insufficient power and subsequent train delays that may occur during train failure rescue under the coupled operation mode, failure scenarios for coupled trains are classified. Rescue schemes incorporating measures such as trip cancellation, short-turn reversal, and standby train deployment are proposed to timely restore normal train operations on the mainline. A mixed-integer linear programming model is established, targeting the minimization of deviation from the original timetable and the number of canceled station services. Taking a metro line as an example, the applicability of different rescue schemes for train failures occuring at various locations along the line is analyzed.

Result & Conclusion When a train failure occurs in the middle section of the line, the forward rescue scheme with rear-train coupling generates fewer conflicting routes, allowing more flexible train adjustments at both ends of the faulty section. When a train fails at either end of the line, the forward rescue scheme with faulty train decoupling offers faster operation time and exerts less impact on subsequent trains. Implementing short-turn reversal measures can reduce the number of additional standby trains deployed during operational adjustments. Under the same rescue scheme, compared with scenarios without advance reversal, adopting short-turn advance reversal measures reduces the objective function value by 64.3%.