This study presents the recent application of energy storage devices in electrified railways, especially batteries, flywheels, electric double layer capacitors and hybrid energy storage devices. The storage and reuse of regenerative braking energy is managed by energy storage devices depending on the purpose of each system. The advantages resulting from the use of energy storage devices are presented by observing the results of both verification tests and practical applications in passenger services. Several real installations of energy storage for railways are shown and compared by using the Ragone plot. The effect of the use of energy storage devices on electrified railways of the future is discussed. Finally, a discussion on the recent applications and developments of energy storage devices is presented in this study. The effective use of energy storage devices is characterised on the basis of the specific applications and current trends of the research undertaken by public bodies and manufacturers.

According to the specific requirements of railway engineering, a techno-economic comparison for onboard hydrogen storage technologies is conducted to discuss their feasibility and potentials for hydrogen-powered hybrid trains. Physical storage methods, including compressed hydrogen (CH₂), liquid hydrogen (LH₂), and cryo-compressed hydrogen (CcH₂), and material-based (chemical) storage methods, such as ammonia, liquid organic hydrogen carriages (LOHCs), and metal hydrides, are carefully discussed in terms of their operational conditions, energy capacity, and economic costs. CH₂ technology is the most mature now but its storage density cannot reach the final target, which is the same problem for intermetallic compounds. In contrast, LH₂, CcH₂, and complex hydrides are attractive for their high storage density. Nevertheless, the harsh working conditions of complex hydrides hinder their vehicular application. Ammonia has advantages in energy capacity, utilisation efficiency and cost, especially being directly utilised by fuel cells. LOHCs are now considered as a potential candidate for hydrogen transport. Simplifying the dehydrogenation process is the important prerequisite for its vehicular employment. Recently, increasing novel hydrogen-powered trains based on different hydrogen storage routes are being tested and optimised across the world. It can be forecasted that hydrogen energy will be a significant booster to railway decarbonisation.

Electrical and electronic components are very important subcomponents in modern industrial wind turbines. Complex multimegawatt wind turbines are continuously being installed both onshore and offshore, continuously increasing the demand for sophisticated electronic and electrical components. In this work, most critical electrical and electronic components in industrial wind turbines have been identified and the applicability of appropriate condition monitoring processes simulated. A fault tree dynamic analysis has been carried out by binary decision diagrams to obtain the system failure probability over time and using different time increments to evaluate the system. This analysis allows critical electrical and electronic components of the converters to be identified in different conditions. The results can be used to develop a scheduled maintenance that improves the decision making and reduces the maintenance costs.

Many railway vehicles use diesel as their energy source but exhaust emissions and concerns about economical fuel supply demand alternatives. Railway electrification is not cost effective for some routes, particularly low‐traffic density regional lines. The journey of a regional diesel–electric train is simulated over the British route Birmingham Moor Street to Stratford‐upon‐Avon and return to establish a benchmark for the conceptual design of a hydrogen‐powered and hydrogen‐hybrid vehicle. A fuel cell power plant, compressed hydrogen at 350 and 700 bar, and metal‐hydride storage are evaluated. All equipment required for the propulsion can be accommodated within the space of the original diesel–electric train, while not compromising passenger‐carrying capacity if 700 bar hydrogen tanks are employed. The hydrogen trains are designed to meet the benchmark journey time of 94 min and the operating range of a day without refuelling. An energy consumption reduction of 34% with the hydrogen‐powered vehicle and a decrease of 55% with the hydrogen‐hybrid train are achieved compared with the original diesel–electric. The well‐to‐wheel carbon dioxide emissions are lower for the conceptual trains: 55% decrease for the hydrogen‐powered and 72% reduction for the hydrogen‐hybrid assuming that the hydrogen is produced from natural gas.

Diesel is the most common energy source used by many railway vehicles globally but it also has an impact on the environment due to carbon emissions from the diesel engine. Railway electrification is an effective way to reduce emissions but fails to be a very cost effective solution particularly for routes where passenger traffic is low. This study has undertaken a propulsion system concept design based on a vehicle similar to the British class 150 diesel‐powered vehicle. A return journey was simulated over the British regional route Birmingham Moor Street to Stratford‐upon‐Avon to set a benchmark for the development of hydrogen‐powered and hydrogen‐hybrid trains. A fuel cell power plant and hydrogen compressed at 350 bars were used as part of the concept design. It was found that all the components essential for the train propulsion system can be installed within the space available on original diesel‐powered class 150 train. The installation of equipment does not compromise passenger capacity and weighs similar to original class 150. Energy consumption was reduced by 44% on the hydrogen‐powered train and by 60% on the hydrogen‐hybrid train. Carbon‐dioxide emissions were reduced by 59% using the hydrogen‐powered train and by 77% using the hydrogen‐hybrid train.

The simulation of railway systems plays a key role in designing the traction power supply network, managing the train operation, and making changes to timetables. Various simulation technologies have been developed to study the railway traction power network and train operation independently. However, the interactions between the load performance, train operation, and fault conditions are not fully understood. This paper proposes a mathematical modeling method to simulate the railway traction power network with a consideration of a multi-train operation, driving controls, under-voltage traction, and substation fault modes. The network voltage, power load demands, and energy consumption according to the existing operation are studied. The hotspots of the power supply network are identified based on an evaluation of the train operation and power demand. The impact of traction power substation (TPSS) outage and a short circuit on the power supply network have been simulated and analyzed. The simulation results have been analyzed and compared with those of a normal operation. A case study based on a practical metro line in Singapore is developed to illustrate the power network evaluation performance.