Developing future infrastructure systems. Network Rail strategic partnership
Fundamental and applied research underpins many recent technical developments in the rail industry. This leaflet outlines a number of current research projects at the University of Southampton supported through the Strategic University Partnership, addressing the Infrastructure asset theme of the Network Rail Technical Strategy. There are also examples of the University’s wider capability in rail research through the Track 21 programme and others. We provide the science needed to bring about a step change in infrastructure design, construction and maintenance, leading to greater safety, cost efficiency and better reliability. The result will be a sustainable asset contributing to an overall reduction in carbon emissions. As one of the largest and most diverse engineering and environmental science groups in the UK we have an unrivalled ability to provide an integrated, whole systems approach to engineering challenges.
Ballast migration
Earthworks and bridge interaction
Increased train operating speeds on the West Coast Main Line have coincided with the sporadic occurrence of ballast migration. Our research will help to identify the fundamental mechanisms of this phenomenon and give insights into the most effective maintenance interventions.
Where earthworks approach bridges the support conditions change. Differential settlement occurs which can lead to hanging sleepers and large dynamic loads. Moreover, granular abutment fills can generate ratcheted pressures against the abutments. We plan to instrument new bridges now being built, to improve the understanding of the interaction between bridges and earthworks.
Modelling random fibre reinforcement of ballast
Using computed tomography to understand ballast fouling
Adding random fibre reinforcement is a promising technique for increasing the resilience of ballasted track. To get a more detailed understanding of the micromechanics involved, a series of numerical analyses is being carried out using Southampton’s unique potential particle based discrete element method.
Ballast fouling adversely affects drainage, increasing the rate of track geometry degradation and reducing the effectiveness of tamping. We are developing a sound scientific understanding of the mechanisms involved, to enable the design of more resilient track.
Discrete element modelling of the micromechanics of ballast By developing a comprehensive understanding of the mechanics of ballast at the particle scale, our research will make possible the rational design of resilient, lowmaintenance ballasted track.
Principal stress rotation New research into principal stress rotation in unsaturated soils reflects real conditions better than the idealised loadings currently used for design. Our work will help engineers predict long term degradation of the sub base in relation to traffic loading, plan maintenance and develop cost-effective remedial measures. Data will also input to an improved track system model
Testing sleepers and ballast in the lab Large scale test rigs simulate the passage of millions of train axles, enabling different combinations of sleepers and ballasts to be tested in the laboratory. Vertical and horizontal dynamic loads can be applied and the response and interaction of the components accurately measured, while a year or more of cumulative tonnage can be reproduced in days.
Trackside noise Noise is produced by both wheel and track. We are investigating the noise produced by different trackforms, including the influence of rail pad stiffness and a comparison of steel and concrete sleepers. Our work on rail dampers offers a potential solution which can more than offset the noise increase due to softer rail pads.
Simulating transport environments and measuring human response Track geometry and defects affect people travelling on the railway. We have unique facilities to investigate track, train and human interactions, facilitating the design of trains in which people can comfortably walk, use the computer, read, eat and drink while the train travels at speed. Our six-axis simulator is used to undertake fundamental and applied research.
Estimating soil water by proxy using low cost sensor arrays Against a background of increased loadings and climate change, subgrade and embankment performance is becoming a major issue. Cheap and reliable means are needed for remotely monitoring soil water content and pressure/suction. We are assessing how reliably low cost, thick-film screen printed sensor arrays can be used to infer water content and pressure.
Measuring wheel/rail roughness and track decay rates Key parameters influencing wheel/rail rolling noise are the rail and wheel roughness and the track decay rates. Our research has led to the development of wheel roughness measurement equipment. Track decay rate measurements allow the influence of different rail pads to be understood, including the effect of temperature. Acoustic scale model tests allow us to improve the prediction models for sound radiation.
Real time bridge scour measurement No available methodologies adequately reveal the physical processes, conditions and extent of scour that might affect the structural performance of bridges. Difficult access and transient features make the extent and impact of scour doubly difficult to determine. Our research applies affordable new sonar technologies to inform decisions related to bridge whole life performance where scour is a major risk factor.
Ground vibration Ground vibration from trains has to be considered along with noise in environmental assessment. Compared with airborne noise, however, there are many complicating factors and predictions are subject to large uncertainty. Our research has led to the development of prediction models for ground vibration from trains, complemented by field measurements of vibration and lab tests of ballast stiffness.
Demand and economic modelling
Tribology
We have developed modelling and appraisal procedures to identify locations for new stations and services, forecast passenger numbers and destinations and calculate benefits and costs. New models will quantify the whole life economic and environmental benefits and costs of improvements to the sub-base, ballast and track system.
Tribology is core to future transport and energy efficient machines, the control of emissions and low maintenance renewable energy systems. Current work includes the investigation of early stage axle-bearing failure, leading to a reduction in in-service failures and increased service intervals; condition monitoring systems to detect rolling element bearing health; next generation lubricants; and transient testing for wear and friction contacts.
Southampton Railway Systems Research (SR2) SR2 brings together research groups across the University to undertake interdisciplinary research and consultancy on railway systems that:
Human factors
−− Is international in scope, covering the UK, Europe and beyond
SR2 conducts fundamental and applied research, provides training and offers consultancy services and advice in comfort, performance and health in vibration and motion environments. We carry out research into the social, cognitive and behavioural aspects of humans in transportation systems. Led by Professor Mike Griffin and Professor Neville Stanton.
SR2 has substantial knowledge, experience and facilities, and an impressive track record of publications and research grant funding.
Railway planning and operations
−− Draws on engineering, physical and social sciences −− Integrates scientific theory with practical applications
Major current projects include the EPSRC-funded T400 study, the EPSRC Track21 Programme Grant (which SR2 leads), a Network Rail Strategic Universities Partnership focusing on infrastructure, and econometrics research for ATOC. We have previously carried out work for a range of clients, including the European Commission, the DfT, Arup, Bombardier, Hitachi, HS1, ORR, RSSB, SNCF and Thales. Members of SR2 have attracted some £10M of funding for railwayrelated research since 2003. Infrastructure Utilising core skills in geomechanics, structures, materials and hydraulics, work on railway infrastructure covers track systems, performance, monitoring and stabilization of earthworks including vegetation and climate effects, and bridge scour. Led by Professor William Powrie. Noise and vibration For many years the University has played a leading role in research into railway noise and vibration, using fundamental models to solve practical problems. Areas covered include rolling noise, ground vibration and ground-borne noise, bridge noise and aerodynamic noise. Led by Professor David Thompson.
SR2 has an extensive track record of research in the fields of rail demand forecasting, capacity modelling, timetabling and the socioeconomic evaluation of both infrastructure and operations. Led by Professor John Preston. Tribology SR2 has developed tribology-based condition monitoring systems and used data fusion techniques from multisensor outputs to detect rolling element bearing health. It also has research programmes into next generation lubricants, transient testing for wear and friction contacts, and failure investigation of bearings. Led by Professor Robert Wood and Dr Ling Wang. Contact us Southampton Railway Systems Research (SR2) Faculty of Engineering and the Environment University of Southampton Highfield Southampton so17 1bj Tel: 023 8059 3960 e-mail: RailResearch@soton.ac.uk Web: www.soton.ac.uk/engineering
Images of computed tomography laboratory and thick-film screen printed sensor: Sharif Ahmed Image illustrating demand and economic modelling contains Ordnance Survey data ©Crown copyright and database right 2013