SUMMARY The geometric alignment of railway track deteriorates with time, primarily due to the sta... more SUMMARY The geometric alignment of railway track deteriorates with time, primarily due to the static and dynamic forces exerted by the trains' wheels on the track. Deterioration of the track's geometry is called track roughness. The paper reports on the outcomes of a study of the deterioration of track roughness on three test sites in Queensland Australia; all three sites are heavy haul lines carrying trains with axle loads above 25 tonnes and more than 50 million gross tonnes of traffic per annum. An examination of measurements of track roughness by Track Recording Vehicles over a 5 year period showed that the rate of increase of track roughness grew with the passage of traffic - this is contrary to the commonly held view that the rate of increase of roughness diminishes with time. A method of presenting track geometry measurements from Track Recording Vehicles is provided which may assist maintenance planners to balance more easily the conflicting demands of reducing maint...
Wheel/rail dynamic forces are dependent upon the characteristics of both train and track, and lea... more Wheel/rail dynamic forces are dependent upon the characteristics of both train and track, and lead to time-dependent degradation of the track. The quality of maintenance of both train and track affect the amplitude of these forces and therefore the rate of degradation of track. These relationships are being studied at Queensland University of Technology via a Rail CRC project, using test track and test vehicles provided by QR. A central part of the study is attempting to relate wheel/rail forces to the longitudinal vertical profile of the track; the profile is measured by QR’s Track Recording Car (TRC) and their Corrugation Analysis Trolley (CAT). However, because doing detailed measurements of the longitudinal profile frequently over the study period is impractical, the authors developed an innovative algorithm that converts track recording car (TRC) rail top offset measurements into suitably accurate longitudinal profiles. The study takes those profiles and correlates them against...
Journal of Professional Issues in Engineering Education and Practice, 1999
Building Networks through Peer Interaction. [Journal of Professional Issues in Engineering Educat... more Building Networks through Peer Interaction. [Journal of Professional Issues in Engineering Education and Practice 125, 159 (1999)]. Martin H. Murray. Abstract. The profession of civil engineering needs graduates with many technical and generic skills. ...
ABSTRACT Track roughness describes in part the up and down waves in the longitudinal geometry of ... more ABSTRACT Track roughness describes in part the up and down waves in the longitudinal geometry of a railway track. A train passing over rough track experiences a degree of bouncing that generates oscillations in the forces exerted by the train's wheels on the top of the rail, which in turn cause this roughness to worsen. The rate at which the track roughness deteriorates depends on the response of the track to the weight of the train and to the dynamic oscillations in wheel/rail forces, which in turn are affected by the properties of the train vehicles' components and the speed of the train. The paper develops relationships between the severity of track roughness and the dynamic wheel/rail forces generated by a moving train using field data, and between those forces and the specific vehicle characteristics of speed, total mass, unsprung mass, suspension stiffness and damping, using NUCARSTM simulations. These two relationships in turn are combined to show how the speed of the train and the design of the train vehicle's bogie suspension can worsen or improve the rate of deterioration of track roughness. The relationships also provide a firm basis for the owner of track to set more representative charges levied on the train operator for using the track.
ABSTRACT At Queensland University of Technology the teaching of engineering science to first year... more ABSTRACT At Queensland University of Technology the teaching of engineering science to first year students has undergone a substantial modification in the past three years. The best aspects of on-cam-pus and distance education have been combined to produce a student-centered program, comprising comprehensive print resources, peer assisted study sessions, tutorials, computer-based exercises, a design-and-build project, and brief context-setting lectures. The paper describes the development and operation of these components of the program and how the change from formal content-driven lecturing has brought about a significant improvement in students' performance in the course. Importantly, the changes have also enabled a reduction in the cost of the course.
The performance of railway track under dynamic loading is extremely complex due to the interdepen... more The performance of railway track under dynamic loading is extremely complex due to the interdependent and sometimes non-linear behaviours of track components. Many and varied computer models of train-track dynamics have been developed around the world to try and analyse these ...
Abstract In Australian rail freight operations, track maintenance costs comprise between 25-35 pe... more Abstract In Australian rail freight operations, track maintenance costs comprise between 25-35 percent of total train operating costs. The main aim of this paper is to describe the results of research into track maintenance planning for the medium to long-term. The paper ...
ABSTRACT A simulation model developed to enable a cost-benefit analysis of sleeper-replacement st... more ABSTRACT A simulation model developed to enable a cost-benefit analysis of sleeper-replacement strategies, using the Weibull distribution, has been updated from a previous version to include up to four different types of sleepers within the track section: steel, concrete, treated timber, and untreated timber. In addition, several changes have greatly increased the number of strategies that can be simulated. The creation of a replacement strategy has been substantially developed to include two separate components, many new frequency and policy options, and the option of continuing a completed simulation with a modified replacement strategy. The model output is designed to give adequate information to the operator to determine the best course of action to take when comparing various possible replacement strategies. The results include the track condition, with the clusters of failed sleepers, and the cost of the replacement strategy. Five distinctly different replacement strategies were simulated for 20 years on a track section with 50,000 mature sleepers. These simulations showed that the nature of the strategy can have very significant effects on the cash flow required from year to year and on the annual demand for replacement materials. Careful investigation is needed to establish compromise strategies that produce acceptable numbers and sizes of clusters of failed sleepers and sleeper life in track while not exceeding available funding and materials.
SUMMARY The geometric alignment of railway track deteriorates with time, primarily due to the sta... more SUMMARY The geometric alignment of railway track deteriorates with time, primarily due to the static and dynamic forces exerted by the trains' wheels on the track. Deterioration of the track's geometry is called track roughness. The paper reports on the outcomes of a study of the deterioration of track roughness on three test sites in Queensland Australia; all three sites are heavy haul lines carrying trains with axle loads above 25 tonnes and more than 50 million gross tonnes of traffic per annum. An examination of measurements of track roughness by Track Recording Vehicles over a 5 year period showed that the rate of increase of track roughness grew with the passage of traffic - this is contrary to the commonly held view that the rate of increase of roughness diminishes with time. A method of presenting track geometry measurements from Track Recording Vehicles is provided which may assist maintenance planners to balance more easily the conflicting demands of reducing maint...
Wheel/rail dynamic forces are dependent upon the characteristics of both train and track, and lea... more Wheel/rail dynamic forces are dependent upon the characteristics of both train and track, and lead to time-dependent degradation of the track. The quality of maintenance of both train and track affect the amplitude of these forces and therefore the rate of degradation of track. These relationships are being studied at Queensland University of Technology via a Rail CRC project, using test track and test vehicles provided by QR. A central part of the study is attempting to relate wheel/rail forces to the longitudinal vertical profile of the track; the profile is measured by QR’s Track Recording Car (TRC) and their Corrugation Analysis Trolley (CAT). However, because doing detailed measurements of the longitudinal profile frequently over the study period is impractical, the authors developed an innovative algorithm that converts track recording car (TRC) rail top offset measurements into suitably accurate longitudinal profiles. The study takes those profiles and correlates them against...
Journal of Professional Issues in Engineering Education and Practice, 1999
Building Networks through Peer Interaction. [Journal of Professional Issues in Engineering Educat... more Building Networks through Peer Interaction. [Journal of Professional Issues in Engineering Education and Practice 125, 159 (1999)]. Martin H. Murray. Abstract. The profession of civil engineering needs graduates with many technical and generic skills. ...
ABSTRACT Track roughness describes in part the up and down waves in the longitudinal geometry of ... more ABSTRACT Track roughness describes in part the up and down waves in the longitudinal geometry of a railway track. A train passing over rough track experiences a degree of bouncing that generates oscillations in the forces exerted by the train's wheels on the top of the rail, which in turn cause this roughness to worsen. The rate at which the track roughness deteriorates depends on the response of the track to the weight of the train and to the dynamic oscillations in wheel/rail forces, which in turn are affected by the properties of the train vehicles' components and the speed of the train. The paper develops relationships between the severity of track roughness and the dynamic wheel/rail forces generated by a moving train using field data, and between those forces and the specific vehicle characteristics of speed, total mass, unsprung mass, suspension stiffness and damping, using NUCARSTM simulations. These two relationships in turn are combined to show how the speed of the train and the design of the train vehicle's bogie suspension can worsen or improve the rate of deterioration of track roughness. The relationships also provide a firm basis for the owner of track to set more representative charges levied on the train operator for using the track.
ABSTRACT At Queensland University of Technology the teaching of engineering science to first year... more ABSTRACT At Queensland University of Technology the teaching of engineering science to first year students has undergone a substantial modification in the past three years. The best aspects of on-cam-pus and distance education have been combined to produce a student-centered program, comprising comprehensive print resources, peer assisted study sessions, tutorials, computer-based exercises, a design-and-build project, and brief context-setting lectures. The paper describes the development and operation of these components of the program and how the change from formal content-driven lecturing has brought about a significant improvement in students' performance in the course. Importantly, the changes have also enabled a reduction in the cost of the course.
The performance of railway track under dynamic loading is extremely complex due to the interdepen... more The performance of railway track under dynamic loading is extremely complex due to the interdependent and sometimes non-linear behaviours of track components. Many and varied computer models of train-track dynamics have been developed around the world to try and analyse these ...
Abstract In Australian rail freight operations, track maintenance costs comprise between 25-35 pe... more Abstract In Australian rail freight operations, track maintenance costs comprise between 25-35 percent of total train operating costs. The main aim of this paper is to describe the results of research into track maintenance planning for the medium to long-term. The paper ...
ABSTRACT A simulation model developed to enable a cost-benefit analysis of sleeper-replacement st... more ABSTRACT A simulation model developed to enable a cost-benefit analysis of sleeper-replacement strategies, using the Weibull distribution, has been updated from a previous version to include up to four different types of sleepers within the track section: steel, concrete, treated timber, and untreated timber. In addition, several changes have greatly increased the number of strategies that can be simulated. The creation of a replacement strategy has been substantially developed to include two separate components, many new frequency and policy options, and the option of continuing a completed simulation with a modified replacement strategy. The model output is designed to give adequate information to the operator to determine the best course of action to take when comparing various possible replacement strategies. The results include the track condition, with the clusters of failed sleepers, and the cost of the replacement strategy. Five distinctly different replacement strategies were simulated for 20 years on a track section with 50,000 mature sleepers. These simulations showed that the nature of the strategy can have very significant effects on the cash flow required from year to year and on the annual demand for replacement materials. Careful investigation is needed to establish compromise strategies that produce acceptable numbers and sizes of clusters of failed sleepers and sleeper life in track while not exceeding available funding and materials.
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