Mathematical optimisation

2 questions for... (1)
Olivier Maurel,
Director of freight information systems at SNCF
Rail & Recherche n°23 - April/May/June 2002

Rail & Recherche: Does freight scheduling pose any specific problems?
Olivier Morel: Managing freight is a lot more complicated than managing passenger traffic. First of all the traffic is very segmented. In passenger traffic there is a certain amount of stability: the Paris-Lyon train runs at regular hours. Freight is not so reproducible. Our problem is that if we do something very rigid, then it is not adapted to customer demand. Hence you have to industrialise wherever possible, while being able to manage any unexpected event.

R & R: What tools are you developing?
O. M.: We have looked into a certain number of approaches based on optimisation techniques. But it remains quite modest. For the very short-term future, we have preferred introducing the notion of traceability of all the modifications that are made to the system and let a human being be the only decision-maker. We have designed Gédéon which collects different information from the traffic and presents it in graph form. One obtains a data base which re-traces everything that has occurred on a specific part of the traffic. This data could be used when discussing the best strategies to apply in order to deal as efficiently as possible with a situation that has occurred.