A systemic framework for monitoring energy performance of urban railways

PhD ThesisGlobal sustainability challenges are particularly acute in urban conurbations which house the majority of the world’s population and where most of the economic activity takes place. Mobility is at the core of this challenge as transport is one of the highest energy consuming and polluting sectors across the globe. Achieving a low environmental impact transport system fit for all is a clear objective. A modal shift to low energy but highly competitive transport modes is a key target. Urban railway systems have the environmental performance and mass transit capability to be the core provider of mobility in metropolitan areas bringing also other benefits e.g. connectivity, cohesion and social inclusivity. Nevertheless, in a very competitive context where all modes are improving their energy performance, it is crucial that urban rail systems enhance their energy conservation levels without jeopardising their service offer. There is a lack of consensus amongst stakeholders on how to assess energy performance of urban rail systems. This void has been extended to the academic literature, where the issue is largely missing. The overall purpose of this thesis is to contribute to energy conservation of urban rail systems by supporting the decisionmaking process leading to the deployment of interventions aimed at improving energy efficiency and optimising its usage. A three-phased methodological triangulation approach has been adopted to address three research questions derived from two research objectives. This research has investigated energy usage, interventions and interdependencies that are governed by the complexity of the socio-technical system that are urban railways. A holistic approach has been developed based on an adaptable systemic monitoring framework and associated methodology enabling i) a multilevel analysis of system energy performance using a set of twenty-two hierarchical indicators and four complementing parameters, ii) an appraisal of candidate energy optimisation interventions and iii) the monitoring of the results of implemented measures. To validate and illustrate its execution, the framework has been applied to five different urban rail systems to assess a total of eleven technical and operational interventions. This has resulted in observing up 3.4% or circa 4 GWh usage reduction at system level when considering the influence of the three technical interventions monitored and up to 4.8% or circa 6.6 GWh when the eight operational interventions are evaluated in conjunction. These outcomes have illustrated the universality of the framework and its adaptability to the particularities of each urban rail system.CleanER-D and OSIRIS grants, both co-funded by the European Commissio

The Gaia mission

Gaia is a cornerstone mission in the science programme of the EuropeanSpace Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging approach. Both the spacecraft and the payload were built by European industry. The involvement of the scientific community focusses on data processing for which the international Gaia Data Processing and Analysis Consortium (DPAC) was selected in 2007. Gaia was launched on 19 December 2013 and arrived at its operating point, the second Lagrange point of the Sun-Earth-Moon system, a few weeks later. The commissioning of the spacecraft and payload was completed on 19 July 2014. The nominal five-year mission started with four weeks of special, ecliptic-pole scanning and subsequently transferred into full-sky scanning mode. We recall the scientific goals of Gaia and give a description of the as-built spacecraft that is currently (mid-2016) being operated to achieve these goals. We pay special attention to the payload module, the performance of which is closely related to the scientific performance of the mission. We provide a summary of the commissioning activities and findings, followed by a description of the routine operational mode. We summarise scientific performance estimates on the basis of in-orbit operations. Several intermediate Gaia data releases are planned and the data can be retrieved from the Gaia Archive, which is available through the Gaia home page. http://www.cosmos.esa.int/gai

The Influence of Operating Strategies regarding an Energy Optimized Driving Style for Electrically Driven Railway Vehicles

The aim of this paper is the optimization of velocity trajectories for electrical railway vehicles with the focus on total energy consumption. On the basis of four fundamental operating modes—acceleration, cruising, coasting, and braking—energy-optimal trajectories are determined by optimizing the sequence of the operating modes as well as the corresponding switching points. The optimization approach is carried out in two consecutive steps. The first step ensures compliance with the given timetable, regarding both time and position constraints. In the second step, the influence of different operating strategies, such as load distribution and the switch-off of traction components during low loads, are analyzed to investigate the characteristics of the energy-optimal velocity trajectory. A detailed simulation model has been developed to carry out the analysis, including an assessment of its capabilities and advantages. The results suggest that the application of load-distribution techniques, either by a switch-off of parallel traction units or by a load-distribution between active units, can affect the energy-optimal driving style

Use of Dynamic Analysis to Investigate the Behaviour of Short Neutral Sections in the Overhead Line Electrification

The ‘short’ neutral section is a feature of alternating current (AC) railway overhead line electrification that is often unreliable and a source of train delays. However hardly any dynamic analysis of its behaviour has been undertaken. This paper briefly describes the work undertaken investigating the possibility of modelling the behaviour using a novel approach. The potential for thus improving the performance of short neutral sections is evaluated, with particular reference to the UK situation. The analysis fundamentally used dynamic simulation of the pantograph and overhead contact line (OCL) interface, implemented using a proprietary finite element analysis tool. The neutral section model was constructed using physical characteristics and laboratory tests data, and was included in a validated pantograph/OCL simulation model. Simulation output of the neutral section behaviour has been validated satisfactorily against real line test data. Using this method the sensitivity of the neutral section performance in relation to particular parameters of its construction was examined. A limited number of parameter adjustments were studied, seeking potential improvements. One such improvement identified involved the additional inclusion of a lever arm at the trailing end of the neutral section. A novel application of pantograph/OCL dynamic simulation to modelling neutral section behaviour has been shown to be useful in assessing the modification of neutral section parameters

Rail and multi-modal transport

This paper elaborates on the definitions of inter and multi-modal transport, as well as their differences in terms of performance. A survey of the barriers, both internal and external, to an efficient intermodal transport is included followed by an analysis of the advantages and disadvantages of combining rail transport with the other transport modes. Transhipment technologies for efficient freight service and some examples of freight rail corridors between sea and inland terminals are presented. The integration between air and rail transport is discussed and the potential synergies between air and high-speed rail services are emphasised. The paper concludes with a discussion on energy use for sustainable rail performance

Energy assessment in Shift2Rail European Rail Research Program

Shift2Rail (S2R) is a major European initiative with research and innovation focused on strengthening the role of rail in the European mobility system. One high-level objective of the S2R research projects FINE1 (Future Improvements on Noise and Energy) and OPEUS (Modelling and Strategies for the Assessment and OPtimisation of Energy USage Aspects of Rail Innovation) is to systematically assess and benchmark the impact of innovative technologies regarding both energy demand as well as costs in European railway system. This includes the development and the implementation of an appropriate methodology, the definition of representative scenarios (energy baseline) and the evaluation of improvements with respect to the energy key performance indicators (KPI) due to the technical solutions developed in S2R technical projects. The results presented are a single train simulation tool implemented by the affiliated open-call project OPEUS as well as the results of the tool verification process. The energy baseline reference scenarios consisting of representative vehicle datasets and service profiles for the main S2R service categories high speed, regional, urban and freight are presented as well as exemplary results of the energy KPI evaluations in these service categories. The service profiles are derived from previous EU projects (e.g. Roll2Rail [1]) and from the preliminary standard prEN 50591 - "Specification and verification of energy consumption for railway rolling stock"; FINE1 closely cooperates with the standardization group developing this Standard

SNAT2 silencing prevents the osmotic induction of transport system A and hinders cell recovery from hypertonic stress

Under hypertonic conditions the induction of SLC38A2/SNAT2 leads to the stimulation of transport system A and to the increase in the cell content of amino acids. In hypertonically stressed human fibroblasts transfection with two si- RNAs for SNAT2 suppressed the increase in SNAT2 mRNA and the stimulation of system A transport activity. Under the same condition, the expansion of the intracellular amino acid pool was significantly lowered and cell volume recovery markedly delayed. It is concluded that the up-regulation of SNAT2 is essential for the rapid restoration of cell volume after hypertonic stress