Capacity for Freight in Urban Railway Networks—An Analytical Model for Capacity Consumption of Freight Trains in Urban Networks

Abstract

As freight distribution is a growing challenge for metropolitan regions, there are calls to actively reintegrate rail freight into urban logistics. The use of railways in urban transport chains helps mitigating negative externalities such as noise, congestion or pollution. Additional strengths of rail transport are (i) the use of road-independent infrastructure, providing a reliable secondary mean of transport, and (ii) the high energy efficiency, due to the system’s characteristics. Despite the advantages of railways, rail freight in urban areas is marginal. One of the reasons might be the lack of suitable train paths due to diverging train characteristics between passenger and freight trains. This paper focuses on the operation of freight railways in densely used mixed traffic networks against the background of network capacity. It determines whether currently unused capacity can be made available to freight by harmonizing train paths and network utilisation maximized by reducing discrepancies between passenger and freight transport. Since passenger transport is the predominant network user, freight operators need to adapt to its characteristics. The study provides an analytical model to determine the effects of changing train characteristics on capacity consumption. With an exemplary timetable study, the findings from the model are compared to the real railway network. The capacity consumption of freight trains can be decreased, most significantly through an increase of acceleration—by increasing traction or decreasing train weight. In contrast, improving train brakes have limited impact. A change of paradigm of how to operate freight trains seems to be necessary. However, increased operational costs for freight operators needs to be weighed against lower capacity consumption to the infrastructure manager’s profit, such as improved network reliability and additional train paths. The paper concludes with measures to reduce capacity consumption and gives an outlook on the context of urban freight transport, particularly at the road-rail interface.