In this paper, the semi-active suspension in railway vehicles based on the controlled Magnetorheological (MR) fluid dampers is examined, and compared with the semi-active low and semi-active high suspension systems to enhance the running safety, ride quality and ride comfort for a high-speed rail vehicle. Fuzzy logic and chaotic fruit fly control techniques are used as system controllers to determine desired damping forces for front and rear bogie frame with force track-ability of system controllers. A 28 degrees of freedom (DoF) mathematical model of the rail vehicle is formulated using nonlinear vehicle suspension and nonlinear heuristic creep model. The Modified Dahl model is formulated to characterize the behavior of the MR damper. The simulation result is validated using the experimental results. Four different suspension strategies are proposed with MR damper i.e. passive, semi-active low, semi-active high and semi-active intelligent compound controller based on bio-inspired chaotic fruit and fuzzy logic hybrid controller. A comparison indicates that the semi-active controller gives the optimum performance based on frequency and time response analysis for comfort vibration actuation (9.088 to 15.33%), ride quality (14.81–20.73%) and comfort (24.91–27.81%) and it has little influence on derailment quotients, offload factors, as a result, it will not endanger the running safety of rail vehicle.

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Railway vehicle is a complex system comprises of several components and has several degrees of freedom. The railway vehicle moves over the system called railway track which is consisted of different components i.e. rail, rail pad, sleeper, fastening elements, ballast, soil and subsoil etc. Modelling of the track is initiated in year 1860. Since then researchers have formulated different models of track components and track systems to analyse the vehicle behaviour, dynamic interaction at the wheel-rail interface and between the track components itself. This paper reviews the investigations carried out in last 50 years and provides a thorough understanding on dynamic behaviour of different track components.

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Realistic modelling of wheel-rail contact is necessary for true analysis of railway vehicle system. This study reviews the rail-wheel contact models with their related computer software programs in detail. The phenomenon of creepage and creep-force is studied in detail in this paper. An insight is presented to linear and non-linear model developed by Carter, Kalker, Johnson &Vermeulen, Halling, Haines and Ollerton and related programs based on their theories. Advanced wheel-rail contact theory is also reviewed in this paper.