Railway traffic on high density urban corridors: Capacity, signalling and timetable

In the paper a study on the correlation among capacity, block sections length, typology of services and timetables for high density lines such as urban railway corridors is presented. The adopted methodology is explained as well as the use of simulation for the analysis of sensitivity. Stability and robustness of selected timetables are investigated. In particular, railway system’s performances are linked to timetable planning criteria, i.e. to the definition of appropriated recovery times and buffer times, which influence the definition of available capacity. The possibility to find a trade-off value among these parameters is described. In this context the differences between theoretical timetables (which are defined by technical features of infrastructure and rolling stock) and the adopted timetables (which include recovery and buffer times and are functional to a defined level of service) are explained. The estimation of correlations among capacity, block sections length, timetable and operational plan is conceived as a basis to provide guidelines to design new urban railways or to evaluate possible reliability effects of actions on block sections (often with changes on the adopted signalling) or timetables.