Optimization of special freight wagons with small wheel diameter

摘要

A better integration and interoperability between rail and road transportation is a key factor in order to reduce pollution and increase railway freight traffic.rnDevelopment of special freight wagons like "SAADKMS" for the transportation of trucks by railway is a successful solution that is meeting an increasing consensus and popularity among many European countries. In order to accelerate truck loading on wagons and reduce the limitation of normal clearance (structure/vehicle/loading gauges) it is necessary to reduce the wheel diameter as much as possible. This is not a drawback-free solution since an excessive reduction of wheel diameter involves many troubles concerning the stability of the vehicle, maximum axle load, wear of bearings and rolling surfaces of rails and axles. Also designing the braking system is very complicated because the reduced number of encumbrances available makes the placement of internal disks on the axles difficult.rnIn order to solve these problems a very original solution concerning wheelset, wheel profiles and more general bogie design have been applied in the development of "SAADKMS" freight wagons so the resulting vehicle is very different from the conventional one. As a matter of fact, many past experiences and know-how for conventional freight wagons are not applicable for this kind of application, so numerical simulations are very important to deeply understand the behaviour of the system and propose criteria for further optimization.rnThe authors of this paper have developed models on commercial multibody software in order to simulate the behaviour of the "SAADKMS" freight wagon in different conditions (stability, steering performances). Also important results such as position of the contact point or wear-number are shown to be useful parameters for further optimization of the rolling surface profiles.