On‐line reschedule optimization for passenger railways in case of emergencies

This paper deals with a special case of the Vehicle Re‐Scheduling Problem (VRSP) for passenger railways in case of emergencies. These emergencies arise when a service line is disturbed due to a huge and unexpected demand which exceeds the service line capacity. In order to provide a proper response to this type of emergency, an on‐line optimization model based on a discrete‐event simulation model is proposed to provide and support decisions about reassigning vehicles from other lines of the transport system to the disturbed line. The simulation model is based on a dynamic network loading model, a dynamic demand generation model, and a schedule‐based service network. The on‐line optimization model has been solved using two greedy heuristics which automatically generate near‐optimal decisions about vehicle reassignments considering the total time in system for passengers as the minimization criterion. An experimental study, based on a synthetic network and the Madrid Regional Railway network, shows that the second proposed heuristic provides near‐optimal reassignment decisions with short computation times compatible with real‐time use.