Factors influencing the design of a linear rail network for a dedicated freight corridor

The design of a new, linear rail network entails determination of the number and location of sidings in a manner that minimises the total travel times of trains. Given the number of trains that need to be operated and the set of feasible siding locations, we study the influence of the number of siding locations on the travel times of trains along a single track, two‐way railway system. For a fixed number of trains that need to be operated, increasing the number of siding locations beyond a critical threshold offsets any incremental 'meet‐pass' benefits, due to the increased congestion delays incurred by trains at each siding location. A 0‐1 mixed integer programme is developed to determine the optimal number of sidings at each location and the best freight train schedule. A computational study on a real world problem is conducted by varying the number of siding locations for different traffic levels. We observe that there exists an optimal number of siding locations for any given traffic level.