Railway switch and crossing (S&C) systems have a very complex structure that requires not only a large number of components (such as rails, check rails, switches, crossings, turnout bearers, slide chair, etc.) but also different types of components and technologies (mechanical devices to operate switches, electrical and/or electronic devices for control, etc.). This complexity of railway S&C systems makes them vulnerable to failures and malfunctions that can ultimately cause delays and even fatal accidents. Thus, it is crucial to develop suitable condition monitoring techniques to deal with fault detection and diagnosis (FDD) in railway S&C systems. The main contribution of this paper is to present a comprehensive review of the existing FDD techniques for railway S&C systems. The aim is to overview the state of the art in rail S&C and in doing so to provide a platform for researchers, railway operators, and experts to research, develop and adopt the best methods for their applications; thereby helping ensure the rapid evolution of monitoring and fault detection in the railway industry at a time of the increased interest in condition based maintenance and the use of high-speed trains on the rail network.

It is well known that Macpherson strut suspension systems are widely used in light and medium weight vehicles. The performance of these suspension systems can be enriched by incorporating magneto-rheological (MR) dampers and an appropriate dynamic model is required in order to find out the ride comfort and other performances properly in the sense of practical environment conditions. Therefore, in this work the kinematic and dynamic modeling of Macpherson strut suspension system with MR damper is presented and its responses are evaluated. The governing equations are formulated using the kinematic properties of the suspension system and adopting Lagrange's equation. In the formulation of the model, both the rotation of the wheel assembly and the lateral stiffness of the tire are considered to represent the nonlinear characteristic of Macpherson type suspension system. The formulated mathematical model is then compared with equivalent conventional quarter car suspension model and the different dynamic responses such as the displacement of the sprung mass are compared to emphasize the effectiveness of the proposed model. Additionally, in this work the important kinematic properties of suspension system such as camber angle, king-pin angle and track width alteration, which cannot be obtained from conventional quarter car suspension model, are evaluated in time and frequency domains. Finally, vibration control responses of the proposed suspension system are presented in time and frequency domains which are achieved from the semi-active sky-hook controller.

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This paper proposes a model-based fault detection (FD) method with application to railway switch & crossing (S&C) systems. These systems are safety critical assets in the rail network and they daily exposed to harsh working conditions and severe environment, which make them more vulnerable to failures and breakdowns. Therefore, it is critical to implement a condition monitoring (CM) technique to enhance the reliability and the availability of these S&C systems. To-the-end of reducing the scheduled maintenance process and decreasing the possible number of delays and/or accidents. This paper thus, proposes a simple model-based technique, a modified residual-based technique, which can be implemented in the real rail network for FD with application to railway electro-mechanical switch system.

Vehicle stability largely depends on the vibration of the steering system. A four degrees of freedom dynamic model of an automotive steering system with a magneto-rheological damper is presented in this study. Firstly, an equivalent mathematical model of the steering system is developed. The nonlinear equation of motion obtained from the dynamic model is then linearized around its equilibrium point to make it suitable for the design of an appropriate controller for vibration suppression. In this work, a new type of adaptive sliding mode controller is designed for control of the magneto-rheological damper and hence to control unwanted vibration. It is shown that the proposed control logic is very effective for settling steering motion near the equilibrium position. The shimmy vibrations of the wheels are reduced by a considerable amount and the steering system becomes stable. In addition, a comparative work is undertaken between the proposed controller and an ordinary sliding mode controller to demonstrate the advantage of the proposed methodology.