The required objectives in terms of capacity and travel times can be achieved through different combinations of Infrastructure and signalling design (investments), services (timetable) and rolling stock. Usually, the quality of the data and information available is quite low; therefore, the macroscopic or at least mesoscopic approach may be more suitable. In addition, large long-term investments can be made by using a phased approach, solving bottlenecks, and avoiding unnecessary expenses. This approach allows to obtain advantages also in the short and medium term and to minimize the risks associated with traffic forecasts.
