on supply chain problems (e.g., [3, 36]). In our LBBD, the so-called master problem handles the intermodal
transportation problem, whereas a set of subproblems handles the last-mile delivery. Further aspects of interest
include the introduction of appropriate optimality cuts plus subproblems’ relaxation and valid inequalities, all
aiming at strengthening the master problem’s formulation. In particular, inspired by a modern concept of de-
composition schemes, namely Partial Benders decomposition, we retain information of the subproblems to the
master problem, so that a faster convergence is achieved.
Relevant Background. Cross-docking is a logistics concept which includes consolidation points for the
orders, as intermediate stations between the supplying points and the customers. A comparison of the cost-
effectiveness of Cross-Docking and the regular direct-shipment policy is provided by [31], and a model that
combines both approaches is described by [7]. Since Cross-Docking operations occur in our setting, we draw
ideas from [40, 32]. An extended survey on the inclusion of intermediate facilities in freight transport networks
appears in [17]. If the network includes multiple Cross-Docking stations, the multi-depot Location-Routing
problem of [39] and the multi-depot VRPTW of [24] would be of value.
Intermodal networks have long been studied under an optimisation viewpoint [26]. This is not surprising
because they include several alternative topologies [38] and network designs. Notably, our work considers a
hub-and-spoke layout, that is the direct shipment of orders from hubs to customers. In addition to the selection
of the means of transport that will perform the shipment, a logistics supply chain must also consider the delays
of the deliveries: indicatively [21] considers fixed arrival rates and transport times to compute the delays of
the deliveries in a USA road-rail intermodal network. An intermodal network typically includes timetabled
transport services of different modes (rail or ship), in which each service can be performed during multiple
time windows in a planning horizon. As this is also the case in our study, we extend the approach of [29]
that constructs identical copies of transport services that depart in different time instances. Time aspects are
important also for the hub location problem in an intermodal network [4].
Recently, [15] offer a heuristic for transferring hazardous materials through a network of railway or roadway
nodes, thus solving a routing problem under stochastic scenarios. [12] aim to connect inland hubs with ports
through a network under strict time windows, so that a set of containers is shipped by the sea terminals. While
the model of [12] considers containers that are already loaded, the study of [25] includes hubs that are also
charged with the consolidation of orders to vehicles before the latter are routed through a multi-modal network.
All three studies examine realistic instances that are significantly larger than the ones previously examined in
the literature. Therefore, these papers suggest heuristic methods, since a commercial solver cannot respond
in reasonable time. We are quite motivated by these developments, as our approach can handle instances of
analogous size and of broader scope.
The literature on intermodal transportation is enormous, yet the one summarized in Table 1 shows the use of
multiple optimization methods. Although heuristic methods remain of great value, the contemporary landscape
reveals that 3PL provider compete on total cost, thus finding the optimal solution matters. Exact methods are
known to be slow or inappropriate in terms of memory requirements, thus our work exploit the staged nature of
our problem to apply a decomposition scheme. Decomposition-based methods are widely used in transportation
problems, some of them being intermodal [14, 16]. The main framework of our exact approach for this paper
will be Benders Decomposition [9] and, in fact, its logic-based extension [18] (LBBD). The closest study relying
on LBBD is [27], although LBBD has broad applicability [33]. Beyond modelling, the implementation of LBBD
is a non-trivial task as its success depends on the integration of valid cuts and also the combination of MILP
and Constraint Programming (CP) formulations, as nicely discussed in [22]. Recently, the concept of Partial
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