This thesis describes the development of a multi-train simulator in which different train control systems are simulated on a common section of high-speed line operating with four trains. The simulator is used to estimate and compare train knock-on delay performance with different signalling systems. This thesis further demonstrates a train trajectory optimisation work. Four searching approach have been implemented to find, for a specific train, the most appropriate target speed in different areas in order to minimise energy usage and delays. A West Coast Main Line case study is presented in order to assess the operational impact of using optimised train trajectory and different practical train control system configurations combined with three different operating priorities. The result shows that, by using more advanced signalling systems or optimal train trajectories, interactions between trains can be reduced, thereby improving performance. This also has the effect of reducing the energy required to make a particular journey. Simple control systems when coupled with the optimisation process have been shown to have similar performance to the more advanced signalling systems. The use of a dynamic programming allows an objective function to be minimised with the best results and an acceptable computation time.

This study aims to investigate the aerodynamic phenomena of passenger trains by undertaking a series of experimental investigations into the aerodynamics of a Class 43 high speed train (HST). A contextual research background is presented with regards to two significant aerodynamic phenomena - slipstreams and crosswinds. Model-scale experiments were undetaken on a l/25th scale HST model at the TRAIN rig moving model rig facility in order to measure slipstreams at a range of trackside positions and with different ballast heights. Crosswind effects were investigated through two model-scale tests and an extensive campaign of innovative train-based surface pressure measurements onboard an operational HST. A wind tunnel test investigated the flow field and pressure distribution around an HST power car and calculation of aerodynamic loads. A symmetrical pair of pressure taps at the train nose enabled yaw angle to be calculated at full scale. A scale-model test using a crosswind generator was undertaken and the magnitudes of aerodynamic loads compared very favorably with the wind tunnel data. The novel full scale it has been possible it isolate open-air data and gusts, and estimate the overturning forces due to crosswinds by a considered approach to surface pressure measurements.

The effectiveness and efficiency of railway vehicle condition monitoring is increasingly critical to railway operations as it directly affects safety, reliability, maintenance efficiency, and overall system performance. Although there are a vast number of railway vehicle condition monitoring technologies, wayside systems are becoming increasingly popular because of the reduced cost of a single monitoring point, and because they do not interfere with the existing railway line. Acoustic sensing and visual imaging are two wayside monitoring technologies that can be applied to monitor the condition of vehicle components such as roller bearing, gearboxes, couplers, and pantographs, etc. The central hypothesis of this thesis is that it is possible to integrate acoustic sensing and visual imaging technologies to achieve enhancement in condition monitoring of railway vehicles. So this thesis presents improvements in railway vehicle condition monitoring through the integration of acoustic sensing and visual imaging technologies.

As demand for rail transportation increases, greater demand is placed on existing railway infrastructure. This is a particular problem in Europe because railway networks that were built many years ago are required to adapt to accommodate the increased traffic. This adaptation may consist of replacing or upgrading parts of the network, creating new lines or replacing signalling systems but such changes are very costly and sometimes not possible. More efficient approaches to meet the demands of increased traffic include improving the design of timetables and using traffic management strategies to deal with unexpected perturbations to the running of the timetable. A software architecture is proposed that detaches the signalling decision making from simulation software and provides a standard interface between a microscopic simulator and an implementation of an algorithm. The architecture is demonstrated using a railway simulator developed by the author and a number of algorithms are applied to both a simple junction scenario and a more detailed scenario consisting of a portion of the East Coast Main Line (ECML), around Kings Cross in London. A comparison is made between to demonstrate the validity of the approach.

Currently, many railway systems need to be upgraded to meet the demand for rapidly increasing railway capability, environmental concerns and customer satisfaction, while there is a lack of the right models and tools required to support the early decision making stage of railway renewal projects. In this thesis, a new railway selection upgrade process is proposed, which aims to support early stage decision-making in railway renewal projects by finding the most appropriate solutions to take forward for more detailed consideration. The railway selection upgrade process consists of modelling, simulation, split into macros-assessment and micro-simulation, and evaluation. A high-level feasibility analysis model is developed for the macro-assessment, to help engineers efficiently select the most promising upgrade options for further detailed consideration using microscopic simulation. This process provides a quick and efficient way to quantify evaluation functions, based on the 4Cs (capacity, carbon, customer satisfaction and cost) framework, to give a final suggestion on the most appropriate upgrade options. Two case studies, based on the East Coast Main Lines and the Northern Ireland railway network, are presented in order to demonstrate the application and verify the feasibility of the high-level feasibility analysis model and the railway upgrade selection process.

Britain's railway industry is implementing the vision of the system in the next thirty years, as outlined in the Rail Technical Strategy (2012); the main objectives to achieve are: carbon and cost reduction, capacity increase and customer satisfaction. The timetable design process is identified as a key enabler of the strategy's implementation. The current method in use is considered as a lengthy process with little computer support and optimisation. This study tries to overcome the outlined weaknesses of the existing method by proposing a more automated process in which the optimisation of a timetable is a properly design stage. The method has been applied to minimise the total energy consumption of five trains on the Aberdeen-Inverness line, while meeting operational and safety constraints. The results showed a reduction in the total energy consumption of 7%, while the average train total journey time is increased by 1% in comparison with the initial schedule.

Railway safety is very important, as it concerns human lives. Therefore identifying risks from possible failures is vital to maintain the safety of railways. Currently, many mature tools, such as fault tree analysis and event tree analysis, are applied to investigate possible risks to railway safety. However, in many circumstances, the applications of these tools are unable to provide satisfactory results when the risk data is incomplete or there is a high level of uncertainty involved in the risk dataThus it is essential to develop new methods to overcome the weakness of current assessment tools. This thesis introduces an improved intelligent system for risk analysis usingfuzzy reasoning approach (FRA) and improved fuzzy analytical hierarchy decision making process (Fuzzy-AHP), which is specially designed and developed for the railways, and able to deal with the uncertainty in risk assessment.

Railway foundations play an integral role in controlling the stability of the overlying track structure and the maintenance of the overall track geometry. Premature failures of railway track foundation are likely to result in frequent maintenance, which may entail significant costs since railway track foundations are less easily accessible than the other layers of railway track. Premature failures of track foundations may arise if the service loads exceed the design specifications, but may also develop as a result of the shortcomings of the design codes to simulate in situ stress paths, which involve cyclic stress changes in the horizontal as well as vertical direction, which result in principal stress rotation (PSR). Laboratory investigations have suggested that cyclic changes in the horizontal as well as vertical direction may result in a higher rate of plastic strain accumulation than cycling the vertical stress only. The effect of PSR on the soil stiffness is less certain however. Furthermore little consideration has been given to how the gradation of different soils may affect in situ drainage conditions and therefore influence the rate of railway track deterioration during PSR. A knowledge gap exists as to how cyclic changes in the directions of principal stresses may affect the pore pressure and stiffness of soils under different drainage conditions. In order to improve our understanding of the effects of PSR on the long term performance of railway track foundations, a series of laboratory tests were conducted which investigated the effects of cyclic changes in the direction of principal stresses on the pore pressure, stiffness and susceptibility to failure of saturated railway track foundation soils under different drainage conditions. The investigated sand-clay mixes were selected so as to replicate the gradation of an in situ railway track foundation. It was found that even small additions of clay to the volume of a sand significantly affected the response of the mixes during cyclic changes in principal stress direction. Moderate additions of clay in the pore space of a sand reduced the susceptibility to principal stress rotation by reducing the tendency for excess pore pressure generation and by increasing the cyclic shear stress the mixes were able to sustain before rapid plastic strain accumulation occurred. Increases in principal stress rotation below the cyclic shear threshold increased the resilient stiffness of the sand-clay mixes, however once this threshold was exceeded rapid stiffness degradation occurred. Below the cyclic shear threshold, the response of the mixes was stable over a high number of loading cycles and no abrupt fatigue failures were observed. The sand-clay mixes were sensitive to even small changes in the magnitude of PSR near the cyclic shear threshold. Small increases in PSR could trigger the sudden collapse of a previously stable sand-clay mix. Under conditions where the rate of pore pressure dissipation was regulated by the permeability and the volumetric compressibility of the soil, the sand clay mixes with moderate additions of fines were stable over a range of cyclic increases in PSR which correspond to the maximum expected changes in magnitude within the depth of a ballasted railway track foundation.

The Overhead Line Equipment (OLE) is a critical sub-system of the 25kV AC overhead railway electrification system, which is the main method of railway electrification on the British railway network. OLE failures can result in significant delays and pose risks to passenger safety, therefore, inspection and maintenance is undertaken to improve component reliability and uphold the availability of the system. OLE asset management strategies can be evaluated using a life cycle cost analysis that considers degradation processes and maintenance activities of the OLE components. The investment required to deliver the level of performance desired by railway customers and regulators can be based on evidence from the analysis’ results. This thesis presents a methodology for modelling the asset management and calculating the whole life cost of the OLE to allow such analysis to take place. This research has developed a High Level Petri net model to simulate the degradation, failure, inspection and maintenance of the main OLE components in a stochastic manner. The model simulates all the main OLE components concurrently in the same model and fixed time interval inspections and condition-based maintenance regimes are considered. The various dependencies between the different components and processes considered, such as opportunistic inspection and maintenance, are also taken into account. The use of High Level Petri nets allows the processes considered to be modelled in a more accurate and efficient manner in comparison to standard Petri nets. The model is used to calculate various statistics associated with the cost, maintenance requirements and reliability of the individual OLE components and the OLE system over its life cycle. This is demonstrated using an example analysis for a 2-mile section of electrified line, which also describes how the outputs obtained can be used by decision makers to study the performance of the components and the implications of the maintenance strategy evaluated by the model. Finally, a Genetic Algorithm is used in conjunction with the Petri net developed to find the optimum maintenance strategies that result in the lowest total cost of the system. The optimum strategy chosen results in a 15% lower expected total cost and 10% fewer expected failures in comparison to the maintenance strategy currently implemented for the OLE on the British railway network, whilst requiring a similar number of maintenance visits. The methodology presented considers the OLE components and the processes described above in more detail than previous literature associated with asset management and life cycle cost analysis of the OLE. Additionally, the suitability and ways in which Petri nets can be used for modelling the asset management of other large engineering systems, comprised of numerous components with various dependencies, is confirmed. Furthermore, the practical use of the model, as an asset management tool, capable of calculating a comprehensive range of outputs calculated, is demonstrated.

The safe transportation of new and spent nuclear fuel is an essential part of the nuclear fuel cycle. The aim of this thesis was to obtain a more thorough understanding of the mechanical loading acting on heavy nuclear packages during rail transportation. There were two motivating factors for this study. Firstly, the design of equipment used to tie down a package to its conveyance has become more challenging with the recent trend of increasing package mass; often exceeding 100 tonnes. This difficulty is due to the advisory acceleration factors recommended for design. Despite widespread acceptance that the factors ensure safety, it is also recognised that for heavier packages they can be prohibitive and result in over engineered tie down systems. Secondly, transportation imparts complex dynamic mechanical loading on packages and the fuel assemblies within them. There have been no reported instances in the UK of problems caused by fuel vibrations. However international studies have prompted this investigation. A rail wagon and tie down system for a 100 tonne package were instrumented with accelerometers and strain gauges. The measurements were taken during a routine rail journey from Barrow-in-Furness to Sellafield. Continuous data was digitally recorded with a sampling rate sufficient to capture shock and vibrations up to 100 Hz. Accelerometers were selected to measure very low frequencies to capture quasi-static loading. Investigation of the frequency content of the accelerations indicated that digital filtering of the data is necessary to determine the magnitudes of the structural loading on tie downs. A method for designing a suitable filter has been developed. A sensitivity analysis of different filters indicated there is a possibility for over estimating loads based on measured data due to poor filter design. Industrial design of tie downs using FEA requires pragmatic run times. This motivated a comparison of the measured strain time histories with the results of a linear static FEA model. The correlation between measured and predicted strains, was strong at frequencies < 3.5 Hz. A residuals analysis indicated that the model predicted the underlying strain process accurately. The methods described are generic and adaptable. They will aid any future experimental work, to characterise shock, vibration and quasi-static loads acting on nuclear packages and their ancillary equipment.