Abstract
Recently computer control has been popular in train traffic control system, but the rescheduling under disturbed train operation has still been done by dispatching operators. Most of the methods to support the rescheduling operation by computer are only to simulate the future train operation and display it. In the level of changing train order, which is most frequently done, some methods can make decision to help operators. But they are heuristic methods and their decision can't always be globally optimal.
Therefore, in this paper, an optimization method for the change of train order by the branch and bound method is proposed. After operators made outline of schedule by general consideration, this method gives optimal train order about total delay time. Using integer variables corresponding to the change of train order, we formalize this problem as combinatorial optimization problem. It is large scale mixed integer programming problem, but we can get the efficient solution by making use of its special structure. This method takes approach of enumeration method and reflects the nature of this problem on the way of searching tree, enumerating variables and calculating lower bound in the bound operation. Consequently we can get the prospect of optimizing practical size problems in reasonable time. This method is developed for real-time control, but it is also useful for offline use such as evaluation of the heuristic methods or development of new heuristics.
