Towards a new modelling approach for evaluating the capacity of new railway projects

Many studies on extending the Dutch railways in urban areas have been carried out recently. In order to make an appropriate judgement of the real added value of the new building traces, the capacity analysis should be evaluated on network level instead of on individual route level. For example, capacity enlargement for a specific line is not efficient if an adjacent tunnel forms a bottleneck. The total capacity for the whole line relies on this bottleneck, the chain is as strong as the weakest link! To determine the capacity of a railway line other factors can be of influence, such as split-links, moveable bridges and environmental conditions (noise constraints). In this paper a large survey of capacity modelling applications will be described taking into account some of the factors. However, the analysis showed no appropriate models that could cover all these aspects, or were too specific to understand by non-experts. Therefore we specified a new way to model new railway extensions in a transparent way. Based on interviews with actors involved we have been able to determine the most important factors of interest. Furthermore, we defined a functional specification of the new model, which was very well accepted by the end-users. A prototype was finally developed to illustrate the working of the model. This paper will contain a survey of modelling approaches, the functional specifications and the formalisation of the model. The first impression of the prototype seems that it can be very well integrated in the current decision-making procedures and can also be understood by non-experts. In this way the newly developed model can play an important role in evaluating new railway infrastructure projects.