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Optimization in Railways

Optimization in Railways

Senior Research Scientist

Railway systems are large, complex and much interconnected organisms. Because of such complexity, of their huge cost and tremendous impact on society, they need to be carefully planned in every phase - strategic, tactical and operational. However, planning and operating railway transportation systems is extremely hard due to the combinatorial complexity of the underlying discrete optimization problems, the technical intricacies, and the immense size of the problem instances.

Trains movement on a railway network is regulated by the official timetables. In cooperation with the capacity department of the Norwegian railway infrastructure manager (Jernbaneverket), SINTEF developed a tool to define a timetable with passenger and freight trains, in order to maximize the number of freight trains "packed" between passenger trains.

During real-time operations, deviations from the official timetable occur quite often, and this requires fast re-scheduling and re-routing decisions in order to recover the network to its regular status and alleviate delays. Train dispatching is usually carried out by trained personnel. Sintef Optimization developed an automatic train dispatching tool which represents the state-of-the-art in Optimization applied to real-time train traffic management. Each time the status of the network changes, the software computes optimal routes and schedules for the running trains in order to quickly recover from current delays. The solution is then displayed for the dispatchers on a screen as a train graph (standard graphical representation of a timetable).

The dispatching tool developed by SINTEF was in operation in the dispatching central in Stavanger, Norway throughout 2014. For this work, SINTEF received the AIRO 2014 Best Application award.