NedTrain, part of the national Dutch Railway group
(NS group) is responsible for the tender, maintenance
and revision of rolling stock. Trains to be maintained are delivered by NS Travelers,
also part of the NS group. Contracts between NedTrain and NS Travelers specify penalties for
maintenance jobs that do take too long.
Arrival of trains (release times of maintenance jobs) is quite unpredictable. NS travelers decides supply of rolling stock at the very last moment; Exact duration of maintenance jobs is only known after initial inspection jobs, therefore large amounts of uncertainty; Maintenance is performed by a number of teams and each team constructs its own operational schedule.
It is our task to
- design a fast scheduling algorithm for the maintenance problem such that rescheduling is possible in real-time;
- find total solutions maximizing flexibility of maintenance jobs while maintaining makespan;
- find a method to distribute the total maintenance problem into a number of independent subproblems, and provide an exact metric to determine the associated loss of flexibility.