A Green Wave for Barges: Scheduling locks on an inland waterway

ith the increasing share of waterbound multimodal transportation in the logistics chain, inland locks are becoming a major bottleneck whose unpredictable service times may limit the long term viability of inland waterway transport. The introduction of a 'green wave' for barges, similar to road traffic, reduces the waiting times to a minimum and at the same time enables fuel consumption optimization by adjusting the sailing speed to the lock operation schedule. We introduce a mathematical model for the single-chamber serial lock scheduling problem with traffic-dependent capacity constraints and present exact and heuristic optimization methods. The methods' solution quality and convergence speed are compared on a large test set generated from traffic on the Albertkanaal in 2008. Preliminary results show that the (heuristic) Combinatorial Benders' decomposition approach easily tackles small and medium sized instances. The optimization of serial locks promises to be an interesting field of study for the future, especially given its potential influence on the competitive position of waterbound multimodal transportation in today's and tomorrow's logistic chains. It proves to be a challenging problem combining aspects from the open-shop scheduling problem and bin packing.status: publishe