932 research outputs found
Dataset for A transferable method for estimating the economic impacts of track interventions: application to ground-borne noise reduction measures for whole sections of route
No full textThis dataset supports the following paper:
Young, M., Rempelos, G., Ntotsios, E., Blainey, S., Thompson, D., & Preston, J. A transferable method for estimating the economic impacts of track interventions: application to ground-borne noise reduction measures for whole sections of route. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit.</span
A whole life carbon model for railway track system interventions.
No full textThe aim of this thesis is to develop an integrated methodology for investigating the potential for a range of novel interventions to reduce the whole-life carbon footprint and Life Cycle Costs (LCC) of ballasted track. Existing methods for assessing the socio-economic performance of railway infrastructure have often been found wanting. A review of the academic literature in the field has been undertaken and methodologies with the potential to improve the socio-economic modelling of railway infrastructure have been identified. A modelling framework for environmental and financial appraisal has been developed by combining principles of Life Cycle Assessment (LCA) and Life Cycle Cost Assessment (LCCA) approaches. Its applicability has been tested through a range of exemplar case studies. The framework has been first tested at the component level, by examining the whole life carbon footprint and LCC of the four most common railway sleeper types present in the UK railway network. Then it has been expanded, by incorporating a detailed Life Cycle Inventory (LCI) inventory of different Switch and Crossing (S&C) design variants. This enabled the quantification (at the asset level) of the whole life carbon footprint and carbon costs of fifteen (six turnouts and nine crossovers) designs variants. The framework was then extended with the capability of examining the performance of novel modifications to the conventional ballasted track. A methodology based on relative settlement was proposed to adapt the results of laboratory element tests into a suitable input into an existing industry-based track geometry degradation model, allowing the estimation of the carbon footprint and Life Cycle Costs (LCC) at the route level. Finally, test results were applied to two practical case studies, demonstrating the capabilities of the model in evaluating and comparing the long-term performance from the inclusion of seven novel track interventions, so as to assess the case for altering current practice. </p
Dataset for: Endurance testing of STAR resistojet
No full textDataset supports: 'Endurance testing of the additively manufactured STAR resistojet' published in Materials & Design.
This dataset contains .csv files produced during endurance testing of two stainless steel 316L prototype resistojet thruster assemblies. The files are automatically created by a LabVIEW GUI that controls the experiments, and include readings from thermocouples, the thruster power supply, and current and voltage measurements. The file includes measurements related to propellant and thrust which are not populated here as they were not used for these endurance tests. </span
A carbon footprint analysis of railway sleepers in the United Kingdom
No full textThis paper provides an assessment of the lifecycle Greenhouse Gas (GHG) emissions associated with the four most common sleeper (railroad tie or cross-tie in North America) types present in the UK rail network. It estimates the embodied material, process and transport emissions linked with the lifecycle activities of construction, relay/renewal and end-of-life of these variants at low and high traffic tonnage. The analysis suggests that at low traffic loads, the softwood sleepers perform the best over the whole simulated-period. At high traffic loads, the concrete sleepers outperform all other variants in terms of lifecycle CO2e emissions, followed by hardwood, softwood and steel. Regardless of the scenario examined, the steel sleepers perform the worst due to the carbon intensive nature of their manufacturing process. This performance gap is amplified at high traffic loads, as their service life is excessively compromised. The analysis reveals that the end-of-life pathway of timber is a critical determinant of its footprint. Results suggest that the impact of disposing of these sleepers results in their footprint being magnified. Nevertheless, if a minimum of 50% follows the combustion pathway with subsequent heat recuperation, then a GHG reduction potential of between 11% and 18% of their footprint is feasible. From a whole-lifecycle cost lens, for higher tonnage routes, the choice of concrete sleepers results in considerable financial savings. If the infrastructure manager was to install sleepers with stiff under sleeper pads (USPs), it may achieve additional economic and GHG savings, with potential for increasing the latter using recycled carbon-neutral USPs
A transferable method for estimating the economic impacts of track interventions: application to ground-borne noise reduction measures for whole sections of route
No full textThe environmental impacts of noise and vibration are becoming increasingly important in the assessment of new and upgraded railway routes. Vibration from railways propagates through the ground to nearby buildings where it may cause annoyance as feelable vibration or as re-radiated noise. To tackle the adverse effects of ground-borne noise a range of possible interventions are available, including softer rail pads, under-sleeper pads and under-ballast mats. The installation costs of such interventions are generally higher for the higher-performing track types. Additionally, there are potential effects on track maintenance costs which may be positive or negative, for example by reducing sleeper damage or increasing the need for ballast tamping. This study presents a socio-economic analysis of the effects of several interventions to reduce ground-borne noise. By selecting a whole route, the installation and whole-life costs are assessed using Network Rail’s Vehicle-Track Interaction Strategic Model (VTISM) and these are offset against benefits in terms of reduced social costs. Ground-borne noise is predicted at various distances from the alignment using the Modelling of Train Induced Vibration (MOTIV) model and the effect of track interventions is determined as insertion loss spectra. The re-radiated noise within a typical domestic building is then estimated using generic building transfer functions. Geographic Information System tools are used to estimate the population affected by ground-borne noise and their expected level of exposure. The methodology is illustrated using a case study route between Brighton and Portsmouth in the South of England
Developing a generalised assessment framework for railway interventions
No full textWork undertaken on the socio-economic assessment of the installation of under-sleeper pads (USPs) on a busy commuter railway route in Britain, as part of the Track to the Future (T2F) project, was presented at COMPRAIL 2018. This was followed by an expanded, comparative analysis of the same route, comparing the noise-reduction and other costs and benefits of USPs, rail dampers and noise barriers, published in the International Journal of Transport Development and Integration. Such analyses provide useful information and decision-making assistance to infrastructure managers, funders and other stakeholders, but typically require the repeated development of bespoke models of study locations, interventions and effects. The “one-off” nature of these models increases the time and costs required for such studies, and makes it more difficult to compare similar schemes in different locations, or different types of intervention in a single location. There is, therefore, a need for an improved, more generalised and standardised, transferable, replicable and comparison-enabling approach to the socioeconomic assessment of such interventions. Ongoing work on the T2F project entails the development and use of standardised templates to describe the input costs and expected impacts of different infrastructure, rolling stock or operational interventions. These form the inputs to, and part of the development for, T2F of an improved, generalised, ontology-based assessment framework, which is being developed using the West Coastway railway line between Portsmouth and Brighton on England’s south coast as an initial case study. This paper describes the context and rationale for the development of the assessment framework, its components and the methodology being adopted
Endurance testing of the additively manufactured STAR resistojet
No full textThis paper reports the outcome of endurance tests performed on a proof-of-concept design of a high-temperature resistojet thruster. A high-performance resistojet could enable a fully all-electric spacecraft architecture providing all propulsion system functions. The thruster utilises a novel additive-manufactured heat exchanger, consisting of concentric thin-walled cylinders, which act as both a resistive heating element and regenerative heat exchanger. Two complete thruster assemblies were tested, with heat exchangers manufactured from 316L stainless steel using selective laser melting. The two test units were used to investigate the operational endurance and determine life-limiting failure modes of the design. The tests consisted of repeated operational cycling to known temperature limits while under vacuum. Degradation and failure was inferred from electrical characteristics of the thrusters, and X-ray computed tomography imaging was used for non-destructive inspection both pre- and post-testing. The analysis showed that the failure modes are due to thermally-induced stresses resulting from mechanical constraints and temperature gradients. The failures occurred after approximately 40 cycles in the first thruster operating with a current of 25 A, and, in the second thruster, after a total of 300 cycles at 15 A and 217 cycles at 20 A, resulting in two distinctly different failure locations
Railway track deterioration models: a review of the state of the art
No full textThere has been a railway renaissance in Britain since the 1990s, with passenger kilometres approximately doubling between 1990 and 2019. Despite changing habits caused by the COVID-19 pandemic, the latest data show that passenger journeys are almost back to their 2019 levels. Without building new lines (HS2 being not yet open and recently downgraded in scope), increased use has led to increased rates of infrastructure deterioration and a need for more maintenance and renewal to create the capacity on the aged existing railway network to meet this demand. Against this background, there have been on-going efforts in the field of railway track deterioration modelling to limit component failures and prolong the remaining useful life of the infrastructure. Analysis and modelling techniques have become increasingly detailed owing to advances in real-time data-acquisition and computational methods and the emergence of ‘big data’ approaches to interpretation. However, previous studies have generally merely confirmed the complexity of modelling track deterioration. There are few if any systematic reviews of deterioration models aimed at informing infrastructure managers (IM) from a whole-life asset management perspective. This paper addresses this knowledge gap by building on previous research to present a systematic taxonomy of track deterioration models, and proposing a hierarchical classification based on level of detail and functionality
A method for assessing the life cycle costs of modifications to ballasted track systems
No full textTests can be carried out on elements of railway track in a laboratory to assess the potential for particular ballast and sleeper combinations to alter stiffness, reduce settlement, and improve the transfer of stresses between sleeper and ballast. For example, under sleeper pads (USPs) and random fibre reinforcements (RFRs) have been shown to reduce settlement in such tests. However, it is more problematic to apply test results to predict real world field rates of deterioration along the track geometry which is largely a function of differential settlement. This is important, because an understanding of reductions in real world rates of deterioration is necessary to predict life cycle costs (LCC) of such interventions and assess the economic case for altering current practice. This research examines the impact of installing USPs and RFRs on two different routes in the UK: the London-Portsmouth line and a section of the East Coast Main Line (ECML). A simple methodology, based on relative settlement is proposed to adapt the results of laboratory element tests into a suitable parameter for input into the track geometry degradation model, allowing estimation of LCC. The financial savings from installation were found to be slightly higher for the ECML than the Portsmouth line, and higher for USPs than for RFRs. Although these conclusions are based on a UK case study, they could be applicable to any ballasted railway track operation in a developed region facing high maintenance costs and growing demand
Factors affecting trust and communication in global virtual teams
No full textAuthor Georgios GousiasMasterarbeit Universität Linz 2022Arbeit auf den öffentlichen PCs in den Bibliotheken der JKU+Medizin abrufba
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