An innovative framework for the simulation of longitudinal dynamics for long freight trains

In the current logistic landscape, freight train transportation is becoming a pivotal element for fast, environmentally friendly operations. The current push toward enhancing productivity, reducing costs and achieve green operations require to maximize trains length and hauled mass. However, these goals introduce challenges to trains running safety due to the increase of longitudinal forces during braking and traction manoeuvres they cause. To address these critical concerns, an investigation on the longitudinal dynamics of heavy freight trains becomes fundamental. This paper introduces a new software framework designed to simulate and assess the longitudinal dynamics of various freight trains. The software employs a self-assembly logic, thus enabling the construction of entire trainsets with minimal input data from the user on component characteristics. The versatility of this tool is fundamental for optimization purposes, where changes to variables such as the wagon number, train payload distribution and braking characteristics are essential. By presenting this innovative software suite, this work aims at contributing to advance the understanding of freight train dynamics. The software suite is then utilized to solve an optimization problem regarding the best positioning of a second locomotive on long freight trains: its results are found to be in accordance with the current literature.