Design of the running gear for the SUSTRAIL freight vehicle

The authors are working together in the 'SUSTRAIL' project to design an innovative, sustainable freight vehicle for use in new European markets. Market research has determined that the SUSTRAIL freight vehicle needs to run at up to 140km/h with an axle load of up to 25T. In order to reduce the impact of the increased freight traffic a requirement for a 50% reduction in lateral forces on the track has also been set. These very demanding requirements can not be met without a corresponding step change in suspension design. After a thorough review it was therefore decided that the conventional Y25 type suspension was not appropriate for the SUSTRAIL freight vehicle. The Y25 suspension is very common in European railway operations and this brings advantages for operation and maintenance however it does have a high level of longitudinal stiffness after the small amount of longitudinal clearance at the axle box has been exceeded and this can result in relatively poor curving and high lateral wheel-rail forces. As an alternative a modified version of the Y25 suspension with a double Lenoir link primary suspension has been investigated and shown to produce much lower longitudinal primary stiffness while still utilizing standard components and methods which are well established within the railway industry. Computer simulation tools have been used by the project team to optimize the precise geometric design and the component parameters. In order to improve stability of the vehicle and allow higher speed operation it was decided to assess the benefit of linkages providing longitudinal stiffness between the axleboxes using a radial arm. Various previous designs were considered and the final proposal involves a novel cross bracing arrangement. A prototype SUSTRAIL freight vehicle is now being constructed and will be tested in 2015.