The Design Of Emergency Shuttle For Urban Rail Transit

The metro railway is a kind of transport mode with large traffic volume and single moving trajectory. Once an accident happened, a large number of passengers will gather at the local station. If they are not timely evacuated, a great travel delays will be produced. Therefore, the design of emergency shuttle lines by using a reasonable method and assignment of shuttle bus to the line as soon as possible to ensure the operation of metro system have an important significance.In this paper, the choice trend of passengers to the trip mode under the subway emergency is understudied through the scene investigation. The hypotheses are established according to the investigation analysis. For the emergency evacuation problems of the blocked passengers in the simple subway network, the emergency shuttle bus lines are designed. The interrupt types of subway lines between the pair of OD station are concluded. The alternative types of shuttle bus routes are listed. First, the feasible paths generation model is established to search feasible paths between the interrupt OD stations, including the metro transfer, direct shuttle bus and indirect shuttle bus. Secondly, the optimal paths selection model with considering the limit of station capacity is established. The shuttle network is constructed by combining k-short alternate paths and punishment paths. The optimal paths between the interrupt OD stations are selected through passenger flow distribution. k value is determined based on the feedback of the station capacity, k value is increased gradually through the loop algorithm until there is no bottleneck station in the shuttle network, then the initial design scheme is obtained. Finally, with considering the constraints of the shuttle bus resource, the initial shuttle routes are merged and filtered and the final shuttle routes design scheme is gotten.In order to assign the required number of shuttle bused to the shuttle positions from the depot locations in the shortest time when metro railway incidents occur, depot location for emergency shuttle bus need to be layout reasonably. The initial shuttle positions are selected based on the current emergency shuttle scheme used by metro management department usually. Cover structure was constructed based on initial shuttle positions as the centers of the circles, the shuttle demand time as the radius, and arrive time comparison of the bridging bus. The difference between the emergency shuttle for metro railway and general emergency rescue is pointed out: not all the demands generated instantaneously, and shuttle buses only need to arrive before the scheduled time. Reverse cover model based on the delay of the shuttle was established, and the genetic algorithm was design to solve this model.With specific subway network as an example, the schemes of routes design and location under different constraint conditions are analyzed. Research data show that: 1) the shuttle routes design scheme can significantly reduce travel delay of blocked passengers and improve the efficiency of emergency evacuation under the metro railway disruption. 2) It is necessary to maintain number of passengers in the metro railway below the station capacity threshold for ensuring a feasible routing design. 3) Direct shuttle route is preferred for short travel distance, while indirect shuttle route is preferred for longer travel distance.;4) bridging bus resources can be maximized to use by actively seeking supply; 5) depot location have higher sensitivity on the location of initial shuttle positions, bridging demand and the probability of incidents.