An investigation of brake application delays in Australian train brake systems began with a literature review of pneumatic train braking systems. Data located in the review gave examples of brake application delays of pre 1990 designs from the U.K., India and North America. Information on application delays on later Australian designs was scarce. Reading of literature has shown a difference between the Australian and North American control valves in the way the propagation of the pressure reduction rate in the brake pipe is maintained. Control valves of the North American style allow the brake pipe air to be connected for a short time to a small cavity or quick service volume of each valve. The quick service volume is then released to atmosphere. The action of exhausting a small amount of air from the brake pipe helps to ensure a propagation of an adequate pressure reduction rate as it travels to the next valve. Australian control valves rely on the ratio of the volume of brake pipe between control valves and the size of the quick service volume or ‘bulb’ to ensure the propagation of an adequate pressure reduction as it travels to the next valve. The air in a bulb of an Australian valve is not expelled to atmosphere until a brake release is made. The research explored possible reductions in application delays by utilizing an experimental pipe test rack that included 4 control valves and 120 meters of brake pipe. Experiments with different configurations of exhaust orifices or chokes, valves and branch pipe lengths that supplied the valves gave a record acquired by data acquisition of the timing of each valve and the local pressure drop from a valve or each valve for comparison. Experiments with exhaust chokes that gave a reduction drop rate in the brake pipe that approached the minimum required to operate a control valve resulted in instability of the application operation of the control valve. The quick service volume of different sizes was included in the experiments to give comparisons in the propagation of the pressure reduction toward the end of a long train. Further increases into the size of the bulb of a control valve to enhance the propagation features toward the end of a long train are discussed. The branch pipe with different diameters from 12 mm to 20 mm and lengths from 160 mm to 800 mm when fitted to an adaptor pipe bracket were investigated and results show that larger diameters gave larger gulps in the brake pipe. Other components that were studied included the pipe bracket that is fitted on some control valves. The pipe bracket and isolation cock was found to add 282 mm of additional length to the air path and while not changing the operation of the valve, the results showed a smaller drop in local pressure in the brake pipe to assist the pressure reduction rate than shown in valves without pipe brackets.

Today, railroad companies transport many varieties of dangerous goods (DG). Train derailments, especially those involving DG, can be catastrophic in terms of loss of life and environmental damage. In North America, the transportation of DG is governed by regulations published by the Canadian and United State's governments. While the regulation is important in terms of providing overall guidelines, they do not address the problem of optimally positioning DG cars in terms of their potential for derailment and the associated risks. Currently, most rail yard operations do not consider the potential effect of the position of DG cars on the risk of derailment. This research is concerned with the problem of how to place DG cars in a train in the train assembly process so that the overall derailment risk can be minimized. The approach considers both the probability of railway cars derailing en route by position as well as the time associated with additional operations in the rail yard. This work has resulted in a useful decision support tool for assisting rail yard operation managers to achieve an optimum trade-off between derailment risk and operating costs in assembling trains. The merits of this new car placement model are illustrated through a case study of a real railway corridor that connects Barstow Yard in California to Corwith Yard in Chicago over 2100 miles and involves a range of track features. The case study demonstrates that the proposed risk minimization strategy could be implemented with minimal rail yard operation cost.

Today, railroad companies transport many varieties of dangerous goods (DG). Train derailments, especially those involving DG, can be catastrophic in terms of loss of life and environmental damage. In North America, the transportation of DG is governed by regulations published by the Canadian and United State's governments. While the regulation is important in terms of providing overall guidelines, they do not address the problem of optimally positioning DG cars in terms of their potential for derailment and the associated risks. Currently, most rail yard operations do not consider the potential effect of the position of DG cars on the risk of derailment. This research is concerned with the problem of how to place DG cars in a train in the train assembly process so that the overall derailment risk can be minimized. The approach considers both the probability of railway cars derailing en route by position as well as the time associated with additional operations in the rail yard. This work has resulted in a useful decision support tool for assisting rail yard operation managers to achieve an optimum trade-off between derailment risk and operating costs in assembling trains. The merits of this new car placement model are illustrated through a case study of a real railway corridor that connects Barstow Yard in California to Corwith Yard in Chicago over 2100 miles and involves a range of track features. The case study demonstrates that the proposed risk minimization strategy could be implemented with minimal rail yard operation cost.

Inaug.-diss.--Breslau. / At head of title: Mittlere und neuere Geschichte. Lebenslauf. "Literaturverzeichnis": p. 6-10.

Thesis (M.A.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 67-68).

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Methods of predicting the dynamic forces are developed for the cases of vehicles negotiating vertical and lateral track irregularities. The bounds of validity of various models of the track are evaluated, from single degree of freedom, lumped parameter models to the case of a two layered beam on elastic foundation with a moving dynamic load. For the case of the lateral response of a vehicle negotiating a track switch, a finite element model of the track is also developed. The vehicle model developed for-the vertical case contains all the rigid body modes of a four axle vehicle for which primary and secondary suspension can be included with viscous or friction suspension damping. Solution of the vehicle/track interaction problem for these non-linear models is obtained by numerical integration, vehicle and track being connected by the non-linear wheel/rail contact stiffness. The most significant forces are shown to arise from the interaction of the unsprung mass and track resilience, with the vehicle modes also making a significant contribution, particularly in friction damped cases. For the lateral case use is made of an existing model of transient vehicle behaviour containing the wheel/rail contact non-linearities, to which track resilience is added in order to predict the track forces. The model is used to predict the forces which would be anticipated at discrete lateral irregularities such as those to be found at track switches. Once again the interaction with the track introduces modes of vibration which are significant in terms of wheel/rail forces. Comparison is made with experimental results obtained from full scale tests in the field. In one experiment the vertical track forces due to a range of vehicles negotiating a series of dipped welds in the track were measured, and in a second the lateral forces were recorded at the site of an artificially introduced lateral kink. A particular application of the results is in the prediction of the rate of deterioration of vertical and lateral geometry due to dynamic forces. This is to offer an improved understanding of the deterioration mechanism in order to influence the future design of vehicles and track to reduce maintenance costs.

This thesis concerns the noise nuisance that results from the operation of urban railways and reports on a case-study of the impact of the Tyneside Metro on residents living in close proximity to the railway tracks. The study was based upon parallel related surveys in the vicinity of Wallsend and Walkergate, during the period August to November 1983: one, a subjective questionnaire survey of perceived noise-nuisance and the other, an objective set of measurements of the actual noise conditions prevailing there. A review of the methods of current practice in the control or urban railway noise demonstrates that regular maintenance of the rails and train wheels is still the most effective way of keeping noise under control at source. Nevertheless, with high speeds of operation, considerable noise nuisance is likely to be experienced by residents nearby. The Metro is the biggest source of noise and noise-nuisance for people exposed to noise levels of over 60 18H Leq dB(A), although the noise annoyance model constructed from the data showed that half of the annoyance felt by respondents could not be explained. Other factors which affect annoyance include vibration, perception of other transport noises, the subjects' ages and whether or not they own the property they occupy. Metro is generally perceived to be quieter and to cause less vibration than the diesel trains (DMUs) which preceded it. The equivalent continuous noise level (Leq) appears to be the most practical of all the various noise indexes for measuring railway noise annoyance. Finally, informal conversation with respondents in the course of a social survey can provide valuable insight into the mental and psychological processes of perception.

Thesis (M.A.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 74-75).