System analysis of train operations to improve freight flow on high gradient rail bottleneck section with mixed traffic

This paper analyzes the operations of freight trains on high-gradient rail sections, which are common on India’s western and eastern coasts (known as a ghat section). Operations in these sections differ from regular rail operations. Resource usage differs for passenger trains and freight trains and depends on whether the train is ascending or descending the graded section. This creates an imbalance in resource usage and adds complexity to these operations. Priority for passenger trains adds to this complication, making freight train scheduling challenging. This study analyzes different techniques to improve the freight throughput of the graded sections, considering the case study of the Lonavala-Karjat section. Freight trains on this section experience extended delays, leading to a network capacity bottleneck. Identifying the root cause of these delays is not straightforward, as operations are interrelated. Therefore, the study employs a systems thinking approach, beginning with identifying bottleneck resources. A discrete event simulation model is employed due to its ability to replicate complex real-world scenarios and assess the impact of different variables on system performance. Based on the findings, policies are proposed to optimize freight flow on the graded rail section.