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An examination is made of the performance of four and five aspect fixed block signalling, theoretical pure moving block signalling, and a more practical quantised moving block system, when operating under both steady state and perturbed running conditions. For each signalling system, a number of basic geographical components, which are commonly found in a railway network, are analysed in order to determine their maximum capacity for a wide range of steady state operating conditions. An example is included of an algorithm which may be used to combine a number of these basic components to facilitate analysis of a more complex configuration. In the investigation of perturbed operating conditions, a specific delay is imposed on a train, and, with a range of running headways, the resulting delays to subsequent trains are evaluated for each signalling system. Thus, it is possible to decide if a signalling system is stable under a given set of operating conditions. Also, if the system is stable, the total number of trains which experience some delay may be determined. Finally, an examination is made of a line which simultaneously carries high speed trains, operating under moving block, and low speed trains, operating under fixed block signalling.

Given the increased hazards faced by transport corridors such as climate induced extreme weather, it is essential that local spatial hot-spots of potential landslide susceptibility can be recognised. Traditionally, geotechnical survey and monitoring approaches have been used to recognise spatially landslide susceptibility zones. The increased availability of affordable very high resolution remotely-sensed datasets, such as airborne laser scanning (ALS) and multispectral aerial imagery, along with improved geospatial digital map data-sets, potentially allows the automated recognition of vulnerable earthwork slopes. However, the challenge remains to develop the analytical framework that allows such data to be integrated in an objective manner to recognise slopes potentially susceptible to failure. In this research, an evidential reasoning multi-source geospatial integration approach for the broad-scale recognition and prediction of landslide susceptibility in transport corridors has been developed. Airborne laser scanning and Ordnance Survey DTM data is used to derive slope stability parameters (slope gradient, aspect, terrain wetness index (TWI), stream power index (SPI) and curvature), while Compact Airborne Spectrographic Imager (CASI) imagery, and existing national scale digital map data-sets are used to characterise the spatial variability of land cover, land use and soil type. A novel approach to characterisation of soil moisture distribution within transport corridors is developed that incorporates the effects of the catchment contribution to local zones of moisture concentration in earthworks. In this approach, the land cover and soil type of the wider catchment are used to estimate the spatial contribution of precipitation contributing to surface runoff, which in turn is used to parameterise a weighted terrain accumulation flow model. The derived topographic and land use properties of the transport corridor are integrated within the evidential reasoning approach to characterise numeric measures of belief, disbelief and uncertainty regarding slope instability spatially within the transport corridor. Evidential reasoning was employed as it offers the ability to derive an objective weighting of the relative importance of each derived property to the final estimation of landslide susceptibility, whilst allowing the uncertainty of the properties to be taken into account. The developed framework was applied to railway transport earthworks located near Haltwhistle in northern England, UK. This section of the Carlisle-Newcastle rail line has a ii history of instability with the occurrence of numerous minor landslides in recent years. Results on spatial distribution of soil moisture indicate considerable contribution of the surrounding wider catchment topography to the localised zones of moisture accumulation. The degrees of belief and disbelief indicated the importance of slope with gradients between 250 to 350 and concave curvature. Permeable soils with variable intercalations accounted for over 80% of slope instability with 5.1% of the earthwork cuttings identified as relatively unstable in contrast to 47.5% for the earthwork embankment. The developed approach was found to have a goodness of fit of 88.5% with respect to the failed slopes used to parametrise the evidential reasoning model and an overall predictive capability of 77.75% based on independent validation dataset.

The Birmingham Maglev developed over fifteen years ago has successfully demonstrated the inherent advantages of low speed maglev over comparable wheeled systems. It remains the only commercially operational Maglev in the world today. To develop the next generation of Maglev vehicles which will overcome some of the limitations of the Birmingham system, such as chassis length and cost, the following issues are addressed in this thesis. 1) The possibility of interaction between the chassis resonant frequencies and the suspension control system causing poor ride quality and at worst instability, are formally analysed. In the Birmingham vehicle a stiff chassis (fundamental bending mode 40Hz) is used avoiding significant interaction with the suspension controller. Using advanced control strategies the low frequency chassis resonances can be controlled allowing a vehicle structure to be used with a fundamental bending mode of about 12Hz. 2) A modem control strategy is developed which delivers an improved ride quality compared with the present classical control system despite having to operate with a 'soft' chassis. Kalman filters are digitally implemented and conclusions drawn about their performance. The classical control strategy is also successfully demonstrated on a 3 m long 'flexible beam' rig. 3) An associated Maglev suspension problem for the response to ramp inputs such as the transition onto gradients which causes either a large steady state tracking error or a worsening ride quality is addressed by modern control theory using integral feedback techniques and classical theory using third order filters. These controllers are globally optimised by a multi-objective parameter optimisation system which formally considers the conflicts inherent in a suspension system between response to stochastic inputs and deterministic inputs.

High-speed trains have become one of the main means of public transportation around the world. The use of tilting train technologies on high-speed trains has contributed to cost effectiveness by reducing journey time between two places without the need to develop a new high-speed rail track infrastructure. Current technologies in tilting railway vehicles use a 'precedence' control scheme. This scheme uses a measurement from the front vehicle to capture 'precedence' information. Research on local sensor loop control strategies is still important to overcome the complexity of using precedence control technique. Work using conventional and modern control approaches has been investigated by previous researches. This study further extends these by investigating a particular intelligent control technique using fuzzy logic in designing the local feedback tilt control scheme.

Longitudinal shock is a familiar but little understood railway problem. A theoretical understanding and practical investigation are described. Theoretical considerations contains seven sections. Fundamentals of impact and design of hydraulic buffers are described first. Effect of wagon configuration on impact, performance is then calculated. Fundamentals of train shocks describes linear spring theory, and its extension to non-linear shock absorbers for trains coupled without and with free slack. Effect of wagon configuration on train shocks is shown. The in-train performance of hydraulic buffers is analysed. Design of an American cushion unit is given. Experimental work is divided into two sections, titled impact and train shocks. The first section contains three subjections, consisting of impact tests with hydraulic buffers on block wagons, and on actual wagons, and impact, test of American cushion unit. The second section comprises five sub-sections. Run-in tests employed rake impacts as a simulation for train run-in. Results from these tests are analysed. Run-out tests used controlled shocks in a short, train to study run-out with various drawgears. Results of the run-out tests are analysed in the next sub-section. The final sub-section describes tests with 70 wagon trains. One train was fitted with hydraulic buffers and drawgear. The other train was fitted with hydraulic buffers and ring spring drawgear. Performance simulation for a hydraulic cushion unit is described. This mathematical model reproduces test results, and enables characteristics for a cushion unit under any condition of impact or train running to be calculated. The influence of brake performance on train shocks is discussed. Buffer performance during braking of fully fitted trains is analysed. The requirements for optimum design of shock absorbing systems, together with the requirements for smooth train operation and the influence of brake performance on train shocks are given in the conclusion.

This thesis is divided into two sections, the first section deals with compacted, dry crust clay in road embankments. The second section deals with the design and construction of an instrument to measure the settlements and horizontal strains in compacted fills. The tests performed on the compacted clay are divided into two groups: a) Tests on laboratory treated and compacted samples. b) Tests on field compacted samples. Triaxial tests are used with low friction end plates and the pore-pressures are measured by using a ceramic probe at midheight of the samples. Standard consolidation and dissipation tests are performed on laboratory compacted samples and tests are performed to study the increase in strength with time on compacted samples. Data from compacted fills are presented and discussed, soil parameters are choosen and stability calculations are performed. Pore-pressures are measured in a compacted fill, and the results are reported. A new instrument for the measurement of vertical settlements and horizontal strains is presented with a complete field measuring system. Examples from actual measurements are given. Conclusions are drawn at the end of each section. Curves, tables and photographs are given in the Appendix.

Lean concrete has, on account of its high stiffness, excellent load-spreading properties when used as a roadbase material in flexible pavements, although on the same account, appreciable stresses arise when movements are restrained by the subgrade or sub-base. Consequently, owing to the low tensile strength of the material, temperature falls result in the formation of cracks which, if sufficiently wide, may be transmitted through the superimposed bituminous surfacing. Developments in the design of flexible pavements and in the specification and use of lean concrete roadbases are reviewed, followed by a consideration of the causes of cracking. Expressions for the spacing and width of cracks resulting from restrained thermal contraction of a cementitious roadbase are derived in terms of the temperature fall, material properties and a constant frictional coefficient, in order to identify the critical parameters involved in each case. Thermal movement measurements were carried out on a number of cement stabilised materials in various moisture conditions and an apparatus which would cause cracking of lean concrete by restrained thermal movement was designed and built. A programme of tests was devised principally to determine the susceptibility of the material to cracking as a function of age, the results indicating that cracking in lean concrete roadbases is likely to occur within one day of placing. Additional tests were carried out to investigate the effects of inadequate compaction, the use of mixes of higher water content and cement content and the incorporation of steel fibres. It was found that mixes of increased tensile strength were more resistant to cracking, especially at early ages, but that they ultimately give rise to wider cracks which would be more likely to reflect through the bituminous surfacing. Experimental results and published values of subgrade restraint were combined to give a more accurate estimate of crack spacing and crack width in a lean concrete roadbase at a given age and for a given temperature fall. Temperatures in a newly constructed roadbase were measured and the results used for the prediction of cracking patterns which were found to be- in broad agreement with those detected. The thesis concludes with a review of methods for controlling reflection cracking in flexible roads with cementitious bases.

The prediction of vehicle mobility is an important aspect of vehicle locomotion system design. Mathematical models have been under development for many decades that estimate the tractive capability of large vehicles such as tanks and trucks across off-road terrain. These models have proven to be strongly successful when applied to these larger vehicles, but tend to vary in accuracy when applied to smaller vehicles. In such cases, soil trafficability experiments are often performed to determine whether or not a vehicle can traverse a given type of terrain. Unfortunately, this method of vehicle testing has limited applicability for planetary exploration vehicles, because planetary soils are almost non-existent on Earth. Various planetary soil simulants have been developed to replicate some of the mechanical properties of planetary soils, but the success of these in practice varies significantly. A significant limiting factor of traditional planetary vehicles is their inability to traverse the complicated terrain (such as rocks, steep slopes, etc.) of planetary surfaces. Future missions will need to consider more advanced locomotion systems beyond wheels and tracks. Unfortunately, trafficability models for these advanced systems either do not work effectively or do not exist at all. The latter is the case for legged vehicles. This thesis contributes to the understanding of microrover locomotion on planetary soils in various ways. Primarily, an accurate prediction model of legged vehicle mobility on the Martian surface is developed. In order to do so, two soil simulants are proposed and the mechanical properties of each are tested. Significant variation in these properties are exhibited due to varying levels of compaction and varying normal forces, each of which has an impact on the mechanical soil properties and the performance prediction of any vehicle type: wheeled, tracked or legged. In validating these soil properties, non-linearity was conclusively found in the critical shearing strength and the shear deformation modulus for a compressible soil, especially at low normal pressure, thereby challenging the globally accepted Mohr-Coulomb linear' relationship. The validation of a mathematical model to accurately predict the soil forces available to provide forward motion to a legged vehicle and the non-linearity of slip sinkage of a single leg in soil ai'e both conclusively validated experimentally. Simulations are then developed in MATLAB and with the Open Dynamics Engine physics library to evaluate the overall performance of a legged vehicle in Earth-based and planetary soils. Finally, a legged vehicle for planetary exploration is proposed, including the mobility prediction for the vehicle at various locations on the Martian surface. Keywords: legged locomotion, soil trafficability, vehicle mobility, planetaiy exploration, soil simulant, rough terrain. Legged Performance and Traction Prediction Tool, CAPTAIN rover.