随着经济的发展，铁路运量和运能的矛盾日趋突出，对限制口的要求也随之严格，且经常变化。计算机编制运输计划对限制口的调整平衡要适应这种情况，作到灵活、准确、快速、已成为一个新的课题。 With the development of economy, the contradiction between the volume of rail transport and transport capacity has become increasingly prominent. The requirements for restricting the ports have also been stringent and often changed. Computer programming transport plan to adjust the balance of the mouth to adapt to this situation to be flexible, accurate and fast, has become a new topic.