This paper develops a method of planning trains on a general railway yard network so as to minimize the total time or cost of transportation of freight cars. At first the problem is formulated as a mixed integer programming problem and then the difficulty of obtaining an optimal solution is observed. This is a motivation of the development of an approximate method of planning yard pass trains on a general network. Newly developed graph-theoretic analytical tools are useful in developing the formulation of the problem and devising the approximate method for solving it. After describing the algorithm in detail using a small example, the results for a practical problem with nineteen yards are presented. The method when programmed for cdc 3600 and facom 230/60 can solve problems for a network with up to fifty yards in reasonable length of computing time. Finally some extensions of the present method are suggested. (a) for the covering abstract of the symposium, please see irrd abstract no. 224453.
Samenvatting