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To further increase passenger train comfort and handling performances, a mechatronic approach to the design of railway vehicles is necessary. In fact, active systems on board a railway vehicle allow to push design barriers beyond those encountered with just passive systems. The article deals with the development of an electro-mechanical actuator to improve the running behaviour of a railway vehicle, both in straight track and curve. The main components of the active system are a brushless motor and a mechanical transmission, used to apply a longitudinal force between the carbody and the bogie of the vehicle. The actuator is operated in force control. Different control strategies were developed for straight track running, where the aim is to increase the vehicle critical speed, and for curve negotiation, where the goal is to reduce the maximum values of track shift forces. A mathematical model of the railway vehicle incorporating the active control device has been developed and used to optimise control strategies and hardware set-up of the active device and to estimate the increase in operating performances with respect to a conventional passive vehicle. The active control device has then been mounted on an ETR470 railway vehicle, and its performances have been evaluated during in-line tests in both straight and curved tracks

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Some aspects about the influence on the current collection of the aerodynamic action on a pantograph, due to the incoming flow generated by train speed are investigated considering pantograph-catenary dynamic interaction. Starting from the quasi-steady theory formulation of the drag and lift forces on the collectors, and considering the turbulence of the incoming flow, the dynamic variation of the contact force between pantograph and catenary is taken into account, within an already developed simulation model. Aerodynamic coefficients of the collectors are obtained from wind tunnel measurements, and the aerodynamic forces are applied to the collectors of the pantograph. The interrelation among the geometry of the collector suspension, the collector shape, and the level of the incoming wind turbulence, and their effect on the contact force, are all considered in this article by means of numerical simulation. Results concerning the advantage of modifying the shape of the collector are outlined.

As train speed increases, contact wire irregularity affects the quality of current collection more and more. The possibility of achieving the maximum operating speed depends also on the maintenance level of the overhead line (OHL). In the present paper, the influence of contact wire irregularity (in terms of vertical deviation of its position) is investigated both experimentally and by means of numerical simulation of the dynamic interaction of pantograph and catenary. In a first step, the capability of the simulation to reproduce the effect of a singularity in the contact wire height along the line has been tested by comparison with available experimental results. The same model has been subsequently used to perform numerical experiments concerning the effects of several types of distributed defects on the catenary. Afterwards, considering the data generated with the simulation as experimental data, a procedure to find the signature in terms of the contact force of the considered distributed defects on the OHL has been proposed. In this procedure, the contact force is not measured, but estimated from the motion of the pantograph, by means of an application of the extended Kalman filter. The adoption of an estimation procedure for the contact force, instead of a direct measurement, would allow the installation of a measurement system that is much simpler than the one required for the direct measurement of contact force. For this feature, it could be installed, at least in principle, on ordinary trains, allowing to perform an extensive monitoring and diagnostic activity with a large database.

This paper presents wind‐induced response reduction in a very slender building using magneto‐rheological (MR) dampers with lever mechanism. The building presents a case study of an engineered design that is instructive. The paper shows that shear response and flexural response of tall buildings present two very different cases for vibration suppression. MR dampers are implemented optimally in the building to reduce its response in the lateral directions for both structural safety and occupant comfort concerns. A proposed lever mechanism is used with the dampers to improve their performance. The study shows how a lever mechanism can enable application to flexural response and scenarios where the inter‐story drift is not enough for dampers to work effectively. Furthermore, the decentralized bang‐bang controller produced additional improvement to the performance of the MR dampers. Copyright © 2010 John Wiley & Sons, Ltd.