The Netherlands as the ‘Gateway to Europe’ is highly profitable for the Dutch Ministry of Infrastructure and the Environment (Ministry of I&E). To maintain this position, infrastructure investments are required to remove (potential) bottlenecks and to stimulate intermodal transport. This thesis focuses on two (potential) bottlenecks in the inland waterway network, namely the sea lock IJmuiden and inland waterway lock Beatrix. The need for additional locks at IJmuiden and Beatrix has been modelled in macro and micro simulation models, although the actual impact of both locks in the waterway network is unknown. The impact of additional locks is measured in ship arrivals and deadweight capacity of passing ships. To measure the impact, a studied waterway network was developed, consisting of nodes (terminals), links (waterways) and infrastructure components (locks). Differences in impact (i)without and (ii)with additional capacity are measured in a simulation model. To choose an appropriate model, existing macro-, meso and micro- waterway simulation models are evaluated. Since the studied waterway network consists of multiple locks, this type of model becomes appropriate to illustrate the impact of additional locks. Next to existing waterway simulation models, other research fields related to freight transport are also evaluated as limited waterway simulation models are available and lag behind. As existing waterway simulation models run short and lag behind, a new simulation model has been developed to determine the impact of increased lock capacity. The new simulation model illustrates significant differences in ship arrival patterns for the current case (without additional locks) and the future case (with additional locks). It appears to be difficult to prospect future ship arrival patterns and peak arrivals, as ship arrival patterns and peak arrivals are completely different. The impact of additional capacity in the studied waterway is thus difficult to prospect. Future ship arrival patterns at IJmuiden might be managed by traffic management and therefore will decrease future peak arrivals. For Beatrix this is not the case, since ship arrival patterns and peak arrivals will remain or even increase in the future. Thus, even with additional capacity, the Beatrix lock might remain a (potential) bottleneck. Therefore, the impact of additional locks in the network is larger for IJmuiden as they schedule ship arrivals with traffic management. Future research is required to evaluate the implementation of traffic management at Beatrix. Despite the unknown consequences of implementing traffic management, Schuttevaer acknowledges the potential of traffic management and is willing to cooperate. More future research is also required to increase the reliability of ship data registration. Increased lock capacity in inland waterway freight transport is only positive for the short-term ship arrival patterns and peak arrivals. In the long-term, structural traffic management changes are also required to improve inland waterway freight transport. Waterway freight transport has substantial potential to stimulate intermodal transport and to strengthen the Netherlands’ position as the ‘Gateway to Europe’. If the sector, Rijkswaterstaat and the Ministry of I&E can work closely together, the potential can be realized. Otherwise, inland waterway freight transport will be placed at risk.