Simulating freight wagon grouping and scheduling policies for Iran railroad: A study on exhausted emissions of diesel locomotives

As railroad is responsible for a major share of freight transportation compare with other in-land transportation modes, appropriate grouping and scheduling of the freight wagons can lead to significant decrease in emissions exhausted by diesel locomotives. In this study, we evaluated the impact of different freight wagon grouping and scheduling policies by simulating moving trains on Iran’s railroad network. The simulated model is accounting for scheduling, classification and train formation simultaneously. To consider the variation of demand for freight transportation of Iran’s railroad network according to different grouping and scheduling policies, eight scenarios designed in addition to do-nothing. Therefore, the values of main pollutant including〖CO〗_2, 〖SO〗_2, PM, 〖NO〗_x, CO and HC emissions are calculated for each scenario by simulation. Results show that simultaneous implementation of non-necessary grouping policy and flexible scheduling policy can lead to lower amount of total emissions. The conclusion provide useful suggestion on grouping policy for Iran railroad network.