Trains operating with several pantographs are used in Sweden and other countries. The more complex operational conditions, however, cause additional difficulties, i.e. low quality of current collection, increased mechanical wear and electromagnetic interference, due to the poor dynamic behaviour of the system. In order to address these problems, a three-dimensional model for the computational analysis of the interaction between catenary and pantograph is presented and validated in this paper, and the dynamic behaviour of the multi-pantograph system, based on Swedish soft pantograph/catenary systems, is analysed. Parametric studies are performed to investigate cases with different distances between pantographs and with up to three pantographs in use. The relationship between dynamic performance and other parameters, i.e. the number of pantographs in use, running speed and the position of the pantographs, is studied. The results show that an appropriate distance between pantographs and a given type of catenary allow operation on the existing infrastructure with up to three pantographs while maintaining an acceptable dynamic performance at the desired speed.

Process-induced deformation in composite laminates usually occurs during the curing process and is strongly dependent on the cure parameters. To study the influence of the cure parameters on the warpage deformation, an experimental study was carried out with different heating rates and first dwell times. The full-field process-induced deformation was captured by contactless 3 D scanning system to validate the numerical method. Second, a multi-scale thermo-viscoelastic modeling technique was employed to predict the process-induced deformation. The results showed a good agreement between the simulation and experimental deformation, which demonstrates the effectiveness of the numerical model. The influence of six different cure parameters of the vacuum bagging process on the warping deformation and residual stress were considered in the numerical study. Knee points were found on the curves depicting the influence of cure parameters on the maximum residual deformation. Within the manufacturer’s specified range, a slower heating rate of 1.5°C/min reduced the process-induced deformation by 7%, while the other parameters affected the process-induced deformation by less than 1.4%. Meanwhile, the residual stress was also reduced with a slower heating rate. Consequently, a lower heating rate is suggested to reduce both the process-induced deformation and the residual stress for thin parts or the zero-bleeding process.

The contact between pantograph and catenary at high speeds suffers from high dynamic contact force variation due to stiffness variations and wave propagation. To increase operational speed on an existing catenary system, especially for soft catenary systems, technical upgrading is usually necessary. Therefore, it is desirable to explore a more practical and cost-saving method to increase the operational speed. Based on a 3D pantograph–catenary finite element model, a parametric study on two-pantograph operation with short spacing distances at high speeds shows that, although the performance of the leading pantograph gets deteriorated, the trailing pantograph feels an improvement if pantographs are spaced at a proper distance. Then, two main positive effects, which can cause the improvement, are addressed. Based on a discussion on wear mechanisms, this paper suggests to use the leading pantograph as an auxiliary pantograph, which does not conduct any electric current, to minimise additional wear caused by the leading pantograph. To help implementation and achieve further improvement under this working condition, this paper investigates cases with optimised uplift force on the leading pantograph and with system parameter deviations. The results show that the two positive effects still remain even with some system parameter deviations. About 30% of speed increase should be possibly achieved still sustaining a good dynamic performance with help of the optimised uplift force.

Bearings of rail vehicles bear various dynamic forces. Any fault of the bearing seriously threatens running safety. For fault diagnosis, vibration and temperature measured from the bogie and acoustic signals measured from trackside are often used. However, installing additional sensing devices on the bogie increases manufacturing cost while trackside monitoring is susceptible to ambient noise. For other application, structural displacement based on computer vision is widely applied for deflection measurement and damage identification of bridges. This article proposes to monitor the health condition of the rail vehicle bearings by detecting the displacement of bolts on the end cap of the bearing box. This study is performed based on an experimental platform of bearing systems. The displacement is monitored by computer vision, which can image real-time displacement of the bolts. The health condition of bearings is reflected by the amplitude of the detected displacement by phase correlation method which is separately studied by simulation. To improve the calculation rate, the computer vision only locally focuses on three bolts rather than the whole image. The displacement amplitudes of the bearing system in the vertical direction are derived by comparing the correlations of the image’s gray-level co-occurrence matrix (GLCM). For verification, the measured displacement is checked against the measurement from laser displacement sensors, which shows that the displacement accuracy is 0.05 mm while improving calculation rate by 68%. This study also found that the displacement of the bearing system increases with the increase in rotational speed while decreasing with static load.

Improving energy efficiency and reducing CO₂ emissions are becoming very essential worldwide. To encourage the development and application of energy-efficient and low-emission technologies and to increase people's awareness of energy-saving, many energy labelling systems are developed and utilized in most countries. Since energy labelling systems have a significant impact, more and more sectors are developing their energy labelling systems to have their products included. Globally, the transport sector consumes a great proportion of energy and is responsible for considerable CO₂ emissions. Although rail vehicles have relatively high energy efficiency, a labelling system has not been developed in the railway sector, whereas other modes of transport have developed energy efficiency indicators or energy labelling systems. Therefore, it is necessary to develop an energy labelling system for rail vehicles to promote rail transport and develop the technology of rail vehicles. First, this paper gives a review of the existing energy labelling systems. Second, it summarizes the rail needs and rail stakeholders’ interests regarding energy efficiency and corresponding labelling. Last but not least, a proposal for an energy labelling system for rail vehicles is given.

Out-of-round (OOR) wheel often happens to trains, which can cause abnormal vibration. To develop effective countermeasures to minimize the abnormal vibration, it is necessary to study how the wheel OOR wear affects the vehicle vibration. This paper performs an experimental study on the abnormal vibration characteristics of metro trains with out-of-round wheels. The vibration characteristics is identified by the general survey of wheel roughness from special tests. The statistic wheel wear values of all the vehicles in an operating metro lines are studied to investigate the relationship between the wheel wear and the operating mileage. Several re-profiling strategies are implemented to eliminate the abnormal vibration caused by wheel OOR. The results show that the root cause of the abnormal vibration and deterioration of ride comfort is the car-body flexible resonance excited by the wheel OOR wear. Wheel re-profiling is the most effective measure for reducing the vehicle abnormal vibration. By re-profiling all the wheels of a tested metro vehicle, the ride comfort can be improved by 35% ∼ 40% and the axle-box acceleration can be reduced by 40%.