Integrated optimization of bus bridging routes and timetables for rail disruptions

A rail disruption may lead to rapid degradation of the public transportation system. In response to rail disruptions, this study focuses on bus bridging service design considering a routing strategy that combines express and short-turn routes. An integrated optimization framework is proposed to jointly optimize the bus bridging routes and timetables under time-varying demand. A brute-force search method is developed to identify all candidate bus bridging routes. A mixed integer linear programming model is then formulated to solve the route selection, bus deployment, and bus timetabling problem simultaneously. To handle the arising computational challenges in solving this large-scale problem, a tabu search-based heuristic with LP rounding is developed. Numerical studies based on Cranbourne Line, Melbourne, demonstrates the applicability of the proposed approach in practice. The results indicate that the proposed framework can generate high-quality bus bridging solutions in a reasonable time, which allows quick response to rail line disruptions. The bus bridging strategy with multiple routes outperforms the standard bridging route in terms of bus line capacity and passenger travel time.