HEURISTICS ANCIENT AND MODERN - TRANSPORT SCHEDULING THROUGH THE AGES

Heuristics which have been developed for transport scheduling over a l engthy period starting in 1960 are presented. They are generated in re sponse to requirements to solve practical problems, and most are now i n regular use by bus and train companies. Mathematical programming mod els have been formulated for some of the problems, but have been inapp ropriate on their own; in some cases. heuristics have led to a reduced problem which has then been solved by integer linear programming. The paper is designed to illustrate the development of heuristics for a r ange of related problem areas over nearly forty years. It explores the relationships between heuristics and other approaches and emphasises the need to convince users of the suitability of me overall system. Wh ere appropriate, indications are given of difficulties in achieving pr actical implementation.