An aggregate capacity estimation model for the evaluation of railroad passing constructions

The Netherlands Railways operates a double tracked intensively used network of railroads. To expand the transportation capacity, each year a number of infrastructure expansions are considered. The evaluation of these expansions is traditionally done by establishing a set of detailed timetables that serve the forecasted transportation demand and that can be executed with the proposed infrastructure expansion. However, the development of a detailed timetable is a very time consuming process, and therefore leaves little opportunity for comparing many alternatives. In this paper, we present and test an aggregate model that can be used to single out the most promising investment alternatives in the railroad infrastructure, specifically passing constructions. The aggregate model provides the user with insight into the ranking of the various alternatives and additionally gives a relative insight into the theoretical capacity of the proposed infrastructure change.