Impact simulation investigation on freight train draft gear systems

Coupler systems in freight trains are essential for safe operation, as they connect rail vehicles and dampen in-train forces through longitudinal suspensions. Modern rail freight uses various types of draft gears, including steel spring-friction, polymer, polymer-friction, and hydraulic draft gears. The non-linear dynamic characteristics of these draft gears are typically assessed through laboratory hammer impact tests or field collision tests, both of which are time-consuming and costly. Understanding and analysing the impact dynamics of these draft gears in freight train longitudinal impacts is crucial for safety. To address this, a three-dimensional (3D) freight train model was developed using a multibody dynamics approach to theoretically analyse draft gear performance during head-on collisions with a rigid body. Several typical draft gears were selected for simulation, and their dynamic impact performances were compared. This modeling approach provides an effective method for assessing the dynamic characteristics of draft gears.