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In railways, using a track- and ride-quality monitoring system on in-service train has become desirable for coordination and security. Identification of the track- or train-related rough rides via ...

Defects in railway axle bearings can affect operational efficiency, or cause in-service failures, damaging the track and train. Healthy bearings produce a certain level of vibration and noise, but a bearing with a defect causes substantial changes in the vibration and noise levels. It is possible to detect the bearing defects at an early stage of their development, allowing an operator to repair the damage before it becomes serious. When a vehicle is scheduled for maintenance, or due for overhaul, knowledge of bearing damage and severity is beneficial, resulting in fewer operational problems and optimised fleet availability. This paper is a review of the state of the art in condition monitoring systems for rolling element bearings, especially the axlebox bearings. This includes exploring the sensing technologies, summarising the main signal processing methods and condition monitoring techniques, i.e. wayside and on-board. Examples of commercially available systems and outputs of current research work are presented. The effectiveness of the current monitoring technologies is assessed and the p– f curve is presented. It is concluded that the research and practical tests on axlebox bearing monitoring are limited compared to the generic bearing applications.

Signaling power is crucial to an operational railway system as any signaling power failure results in serious operational and financial impacts. Therefore, intelligent condition monitoring and accurate fault location are important for the railway industry. This paper introduces a novel distributed insulation monitoring method for railway signaling power system that can monitor continually the resistive earth leakage current and determine the location of the leakage point by tracking the rectified current difference pattern. This method can be used for extended signaling power distribution networks with multiple branches and requires no external power supply or signal injection.

The harmonic currents injected by high speed electric trains cause not only the pollution of power quality (PQ), but can also excite harmonic resonance in the traction power supply system (TPSS) of high speed railway (HSR). It is essential to build a proper harmonic distribution and prediction model for high speed electric trains. This paper presents an approach to obtain the probability density of harmonic current based on a non-parametric Kernel density estimation method, which can describe the probability distribution characteristics using a data-driven mechanism. A prediction algorithm for harmonic current based on confidence intervals, which can simulate harmonic current injection using a continuous sampling method, is presented in this paper. The new high speed CRH380AL electric multiple units (EMU) are used to illustrate the method. The results show that the proposed approach and algorithm can be useful for harmonic source simulation in harmonic power flow calculation and PQ assessment.

Energy and environmental sustainability in transportation are becoming ever more important. In Europe, the transportation sector is responsible for about 30% of the final end use of energy. Electrified railway systems play an important role in contributing to the reduction of energy usage and CO2 emissions compared with other transport modes. For metro-transit systems with frequently motoring and braking trains, the effective use of regenerated braking energy is a significant way to reduce the net energy consumption. Although eco-driving strategies have been studied for some time, a comprehensive understanding of how regeneration affects the overall system energy consumption has not been developed. This paper proposes a multi-train traction power network modelling method to determine the system energy flow of the railway system with regenerating braking trains. The initial results show that minimising traction energy use is not the same as minimising the system energy usage in a metro system. An integrated optimisation method is proposed to solve the system energy-saving problem, which takes train movement and electrical power flow into consideration. The results of a study of the Beijing Yizhuang metro line indicate that optimised operation could reduce the energy consumption at the substations by nearly 38.6% compared to that used with the existing ATO operation.

Energy efficient techniques are receiving increasing attention because of rising energy prices and environmental concerns. Railways, along with other transport modes, are facing increasing pressure to provide more intelligent and efficient power management strategies. This paper presents an integrated optimization method for metro operation to minimize whole day substation energy consumption by calculating the most appropriate train trajectory (driving speed profile) and timetable configuration. A train trajectory optimization algorithm and timetable optimization algorithm are developed specifically for the study. The train operation performance is affected by a number of different systems that are closely interlinked. Therefore, an integrated optimization process is introduced to obtain the optimal results accurately and efficiently. The results show that, by using the optimal train trajectory and timetable, the substation energy consumption and load can be significantly reduced, thereby improving the system performance and stability. This also has the effect of reducing substation investment costs for new metros.

The majority of electrical failures in wind turbines occur in the semiconductor components (IGBTs) of converters. To increase reliability and decrease the maintenance costs associated with this component, several health-monitoring methods have been proposed in the literature. Many laboratory-based tests have been conducted to detect the failure mechanisms of the IGBT in their early stages through monitoring the variations of thermo-sensitive electrical parameters. The methods are generally proposed and validated with a single-phase converter with an air-cored inductive or resistive load. However, limited work has been carried out considering limitations associated with measurement and processing of these parameters in a three-phase converter. Furthermore, looking at just variations of the module junction temperature will most likely lead to unreliable health monitoring as different failure mechanisms have their own individual effects on temperature variations of some, or all, of the electrical parameters. A reliable health monitoring system is necessary to determine whether the temperature variations are due to the presence of a premature failure or from normal converter operation. To address this issue, a temperature measurement approach should be independent from the failure mechanisms. In this paper, temperature is estimated by monitoring an electrical parameter particularly affected by different failure types. Early bond wire lift-off is detected by another electrical parameter that is sensitive to the progress of the failure. Considering two separate electrical parameters, one for estimation of temperature (switching off time) and another to detect the premature bond wire lift-off (collector emitter on-state voltage) enhance the reliability of an IGBT could increase the accuracy of the temperature estimation as well as premature failure detection.\ud

The inexorable increase in energy demand around the world has put the energy-saving technology in hot spot for railway transportation. Train speed trajectory optimization based on optimal control, coasting control, and collaborative control inside railway systems is a popular methodology to enhance energy efficiency. This paper studies a special and interesting problem, i.e., the partial train speed trajectory optimization problem, and proposes a complete mathematical model where a mixed-integer linear programming algorithm can be directly applied. During the transient operation process of a train, the speed of the train is often considered to be monotonically increasing and decreasing in normal conditions without extreme gradients. Given that, the proposed method can quickly locate the train speed profile under practical engineering constraints, and the objective function is either to maximize the regenerative braking energy or to minimize the traction energy. Such a method with a short computational time may become particularly interesting for online cases where a train is altering its speed in a fixed distance and time due to the operational requirement. The generated speed trajectory can be used to guide the train to control its speed or in a normal braking operation. The robustness and effectiveness of the method has been demonstrated through a number of detailed simulation results in this paper.

Railway Operators and Infrastructure Owners are required to design the railway to specific national and international, technical and safety performance standards. These standards and codes of practice provide the basis for company ‘Codes of Practice’, which detail the design methodology, application and system installation. To validate the design and to comply with these standards and codes of practice, Atkins and the University of Birmingham have developed the multi-train simulator (MTS) to model AC railway electrification infrastructure. The development was carried out under a Knowledge Transfer Partnership between Atkins and the University of Birmingham. The MTS models multiple trains moving on AC traction railway networks following specified timetables. The model of the traction power network covers all types of AC feeding arrangements in the UK, including the rail-return system, the classic booster transformer system and the autotransformer system. This study addresses the work undertaken by the Knowledge Transfer Partnership and describes the development of AC railway electrification infrastructure modelling based on a multi-conductor model for MTS. The modelling of multi-conductors in AC power networks separately, instead of lumping them together, enables more accurate calculations of induced voltage, EMC analysis, return current distribution, positive and negative energy consumptions and loss calculations.

A. Palotie on työryhmän Int IBD Genetics Consortium jäsen. One goal of human genetics is to understand the genetic basis of disease, a challenge for diseases of complex inheritance because risk alleles are few relative to the vast set of benign variants. Risk variants are often sought by association studies in which allele frequencies in case subjects are contrasted with those from population-based samples used as control subjects. In an ideal world we would know population-level allele frequencies, releasing researchers to focus on case subjects. We argue this ideal is possible, at least theoretically, and we outline a path to achieving it in reality. If such a resource were to exist, it would yield ample savings and would facilitate the effective use of data repositories by removing administrative and technical barriers. We call this concept the Universal Control Repository Network (UNICORN), a means to perform association analyses without necessitating direct access to individual-level control data. Our approach to UNICORN uses existing genetic resources and various statistical tools to analyze these data, including hierarchical clustering with spectral analysis of ancestry; and empirical Bayesian analysis along with Gaussian spatial processes to estimate ancestry-specific allele frequencies. We demonstrate our approach using tens of thousands of control subjects from studies of Crohn disease, showing how it controls false positives, provides power similar to that achieved when all control data are directly accessible, and enhances power when control data are limiting or even imperfectly matched ancestrally. These results highlight how UNICORN can enable reliable, powerful, and convenient genetic association analyses without access to the individual-level data.

Train simulation software is conventionally validated by checking simulation results against equivalent data collected from real train runs. It is typically expected that these results will be within 5–10% accuracy of the recorded data. However, such a large margin could allow errors in the programming to be overlooked, resulting in an inaccurate model. This paper presents a method for error checking and validating the kinematics of train simulators based on comparison with calculated results, which are found by solving the fundamental equations governing train motion. A typical train run comprises of a combination of two or more of the four stages: accelerating, cruising, coasting and braking. Each stage is considered as a separate scenario for which the equations must be solved, in order to find the running time, distance travelled and energy consumption of the vehicle. This validation method is applied to two train movement simulators currently used for research. Certain specific scenarios for which analytical solutions are available are run in each simulator. The differences from the analytical solution in each test case are quantified, allowing the simulators to be compared to each other and the exact solution.

In order to reduce energy consumption on DC railways where regenerative braking is not available, train control strategy or ‘driver style’ is a practical alternative. In 2011, instrumentation to monitor energy consumption on the Merseyrail network was fitted to a British Rail Class 508 DC camshaft-operated electrical multiple unit. In this paper, seven services from Hunts Cross to Southport are highlighted to demonstrate a number of driver styles and their correlation with energy consumption. The differences in energy consumption were observed to be related to driver aggression in both the acceleration and deceleration phases.

This paper presents a view of the current state of monitoring track geometry condition from in-service vehicles. It considers technology used to provide condition monitoring; some issues of processing and the determination of location; how things have evolved over the past decade; and what is being, or could/should be done in future research. Monitoring railway track geometry from an in-service vehicle is an attractive proposition that has become a reality in the past decade. However, this is only the beginning. Seeing the same track over and over again provides an opportunity for observing track geometry degradation that can potentially be used to inform maintenance decisions. Furthermore, it is possible to extend the use of track condition information to identify if maintenance is effective, and to monitor the degradation of individual faults such as dipped joints. There are full unattended track geometry measurement systems running on in-service vehicles in the UK and elsewhere around the world, feedin...

Regenerative braking improves the energy efficiency of railway transportation by converting kinetic energy into electric energy. This paper proposes a method to apply the Bellman-Ford (BF) algorithm to search for the train braking speed trajectory to increase the total regenerative braking energy (RBE) in a blended braking mode with both electric and mechanical braking forces available. The BF algorithm is applied in a discretized train-state model. A typical suburban train has been modeled and studied under real engineering scenarios involving changing gradients, journey time, and speed limits. It is found that the searched braking speed trajectory is able to achieve a significant increase in the RBE, in comparison with the constant-braking-rate (CBR) method with only a minor difference in the total braking time. An RBE increment rate of 17.23% has been achieved. Verification of the proposed method using BF has been performed in a simplified scenario with zero gradient and without considering the constraints of braking time and speed limits. Linear programming (LP) is applied to search for a train trajectory with the maximum RBE and achieves solutions that can be used to verify the proposed method using BF. It is found that it is possible to achieve a near-optimal solution using BF and the solution can be further improved with a more complex search space. The proposed method takes advantage of robustness and simplicity of modeling in a complex engineering scenario, in which a number of nonlinear constraints are involved.

The development of reliable methods for measuring deflections as trains pass has enabled valuable insights into railway track behaviour to be gained. This is especially useful for problem areas such as transitions from normal ground onto hard substructures and complex track geometries such as switches and crossings.To date, much of the research on transition zone behaviour has focussed on transitions associated with underbridges and other substructures. Switches and crossings have received some attention and level crossings generally very little. This paper describes and discusses the behaviour of a transition onto a level crossing in the south of England, UK. Measurements are presented from both trackside and on-train instruments. It is found that at this crossing, maintenance constraints have resulted in a group of unsupported or hanging sleepers on the approach to the crossing; and that this fault is not effectively rectified by tamping. Comparisons are also made between the way the fault shows up in measurements from trains of the loaded track profile and data from trackside measurements.

Objectives: The objective of this study was to systematically review the epidemiological evidence for an association between periodontitis (PD) and incident atherosclerotic cardiovascular disease (ACVD), including coronary heart disease (CHD), cerebrovascular disease and peripheral arterial disease. Methods: Systematic review of cohort and case-control studies on the association of clinically or radiographically diagnosed PD and ACVD. Results: Overall, 12 studies were included in this study (six studies on CHD, three studies on cerebrovascular disease, two studies on both coronary heart and cerebrovascular disease mortality and one study on peripheral arterial disease). All but one study reported positive associations between various periodontal disease measures and the incidence of ACVD, at least in specific subgroups. The association was stronger in younger adults and there was no evidence for an association between PD and incident CHD in subjects older than 65 years. Only one study evaluated the association between PD and secondary cardiovascular events. Conclusions: There is evidence for an increased risk of ACVD in patients with PD compared to patients without. However, this may not apply to all groups of the population. There is insufficient evidence for an association between PD and the incidence of secondary cardiovascular events.

With rising concerns on energy and environment, the energy-efficient operation techniques in railway systems are paid more attention in recent years. The metro-transit system has some distinguishing features like short headway and a high number of stations with short interstation distance, which makes effectively using regenerative energy becoming more significant in the energy-saving study. This paper illustrates a system energy optimisation approach to reduce global substation energy consumption, using Monte Carlo Simulation. The conception of substation and regenerative energy estimation is proposed in the optimisation. A railway power network simulation is utilised to validate the energy-saving performance in Beijing Yizhuang Subway Line. After applying efficient-driving strategies remaining current timetable, the substation energy can be reduced by 29.9% compared with current operation. By slightly changing the journey time of each interstation, the substation energy consumption can be reduced by additional 13.8% due to an increasing usage of regenerative braking energy.

Introduction: The classic manifestations of vitamin D deficiency include rickets and osteomalacia. Here we demonstrate a case of vitamin D deficiency presenting as radiologic bone loss around the apical and marginal periodontal tissues, consistent with periapical cemental dysplasia. Potential mechanisms for this are explored and the importance of dentists in managing such cases is discussed.Case Presentation: An 18-year-old female patient was referred with marginal periodontal bone loss. Radiology revealed marginal bone loss and multiple asymptomatic periapical radiolucencies associated with teeth that responded positively to pulp testing. The patient was of Southern Asian descent, wore a headscarf and occlusive clothing for cultural reasons, and was visibly malnourished, reporting a poor diet. A diagnosis of severe vitamin D deficiency was confirmed by serum biochemistry. The patient underwent vitamin D supplementation, after which the radiolucent areas resolved.Conclusions: The prevalence of vitamin D d...

Renewable energy sources have a key role to play in the global energy mix as a means of reducing the impact of energy production on climate change. Wind energy is the most developed of all renewable energy technologies with more than 200 GW of globally installed capacity as of 2011. Analyses of wind farm maintenance costs show that up to 40% of the outlay is related to unexpected component failures that lead to costly unscheduled amendments. Wind farm operators are constantly looking for new technological developments in condition monitoring that can contribute to the minimisation of wind turbine maintenance expenditure. Early fault detection through condition monitoring can help prevent major breakdowns as well as significantly decrease associated costs. Moreover it enables the optimisation of maintenance schedules, reduces downtime, increases asset availability and enhances safety and operational reliability. Faults in the braking system are of particularly concern since they can result in catastrophic failure of the wind turbine. The present study investigates online condition monitoring based on voltages and currents for mechanical wind turbine brake system fault diagnosis.

Aim: A double-blind randomized controlled trial to determine whether dietary supplementation with fruit/vegetable/berry juice powder concentrates, simultaneously with non-surgical periodontal therapy, improved 2-month treatment outcomes. Methods: Volunteers with chronic periodontitis were randomly assigned to one of three groups: fruit/vegetable (FV), fruit/vegetable/berry (FVB) or placebo. Supplements were taken daily during non-surgical debridement and maintenance and outcomes assessed at 2, 5 and 8 months after completion. Primary outcomes were mean probing pocket depth (PPD), clinical attachment gain, % sites bleeding on probing (% BOP) at 2 months. Adherence and plasma b-carotene were determined. Results: Sixty-one nutritionally replete (by serum biochemistry) volunteers enrolled and 60 (n = 20 per arm) completed the 2-month review. Clinical outcomes improved in all groups at 2 months, with additional improvement in PPD versus placebo for FV (p < 0.03). Gingival crevicular fluid volumes diminished more in supplement groups than placebo (FVB; p < 0.05) at 2 months, but not at later times. The % BOP (5 months) and cumulative plaque scores (8 months) were lowered more in the FV group (p < 0.05). Conclusions: Adjunctive juice powder concentrates appear to improve initial pocket depth reductions in nutritionally replete patients, where plasma micronutrient bioavailability is attainable. Definitive multicentre studies in untreated and treated patients are required to ascertain the clinical significance of such changes.

Electric railways collect power from the infrastructure via various current collection systems. For high-voltage AC- and DC-powered railways, this is usually achieved using overhead electrification equipment and a train-borne pantograph. The dynamics of such systems are well understood, and the systems are able to be operated under a range of conditions and speeds. Lower-voltage DC-powered railways ( This article presents some experimental results from a bogie-mounted instrumentation system designed to monitor a typical example of a shoegear assembly operated on the UK railway system. The results indicate that the shoegear broadly performs in accordance with the design guidelines. Several points of loss of contact were observed, and it is shown that the contact force between the conductor shoe and rail can be estimated. The mean force was found to vary with third rail height, but a wide distribution of forces is found at any one height because of hysteresis in the shoegear. Large, but short-term, forces and torques occur because of third rail irregularities and ramps.

Recent increases in railway patronage worldwide have created pressure on rolling stock and railway infrastructure through the demand to improve the capacity and punctuality of the whole system, and this demand must also be balanced with reducing life-cycle costs. Condition monitoring is seen as a significant contributor in achieving this. The emphasis of this article is on the use of sensors mounted on rolling stock to monitor the condition of infrastructure and the rolling stock itself. This is set in the context of modern rolling stock being fitted with high-capacity communication buses and multiple sensors, resulting in the potential for advanced processing of collected data. This article brings together linked research that uses a similar set of rolling stock sensors, and discusses: general usage and benefits, a track defect detection method, running gear condition monitoring, and absolute train speed detection.

John Weston Smith decided on a career in medicine despite coming from a family with no medical background or experience of higher education. His father was a wages clerk for the Midland Red Bus Company and his mother a housewife. John was encouraged in his choice by Margaret Sheldon, the family GP. He lived at home as a student. After qualifying he worked as a registrar in obstetrics at Dudley Road Hospital in Birmingham, but then decided on a career in general practice. He worked as an assistant in a practice in Birmingham but also opened his own practice, with friends and family members as patients, on 5 July 1948, the first day of the NHS. He struggled to find a partnership because he had been a conscientious objector on religious grounds during the war. He moved to a two handed practice in Tamworth, Staffordshire, in 1949, where he …

Railways are expected to operate with ever increasing levels of availability, reliability, safety and security. One way of ensuring high levels of dependability is through the use of condition monitoring systems. This paper presents the results of research on fault detection and diagnosis methods for railway track circuits. The proposed method uses a hybrid quantitative/qualitative technique known as a neuro-fuzzy system. Such a hybrid fault detection and diagnosis system combines the benefits of both fuzzy logic and neural networks, i.e. the ability to deal with system imprecision and to learn by neural network training processes. It is shown that the proposed method correctly detects and diagnoses the most commonly occurring track circuit failures in a laboratory test rig of one type of audio frequency jointless track circuit.

In the future, the dependability of the railway system must be improved to accommodate higher train speeds, greater axle loads, and increased service frequency. One way of increasing the dependability is through improved maintenance and failure management. The collection and processing of information to ascertain the condition of railway infrastructure allows remedial action to be undertaken in a more efficient manner. This paper describes the development of a condition monitoring system based on pattern recognition for detecting and diagnosing point machine failures. It is shown that initially, when data is acquired from a point machine, it is difficult to detect faults. However, upon the application of a moving average filter, fault conditions can be more straightforwardly detected and diagnosed. Using data collected from a set of points under test it is shown that all potentially tested failure modes can be successfully detected and diagnosed.

This paper discusses the maintenance of accurate track alignment. The authors note that accurate track alignment is important in guaranteeing the smooth ride quality and safe passage of railroad vehicles, avoiding both flange contact and flange climb. To accurately measure horizontal track geometry, the authors use a full track geometry recording system comprised of mounted sensors on the bogie of an in-service vehicle. The system estimates the mean track alignment without using either optical or contact sensors. The authors observe that while either a yaw rate or bogie lateral acceleration, in principle, can be processed to estimate mean lateral track irregularity, a yaw rate gyro provides consistent estimates down to lower vehicle speeds. It is noted that yaw rate estimates are more efficient than those of an accelerometer, without needing to compensate for the effects of bogie roll. Also observed is the improved estimate obtained by inverting the dynamic relationship between the mean track alignment and the bogie yaw motion. The research demonstrates this with results from a Class 175 vehicle. The authors conclude that continual monitoring of the lateral response of a bogie on an in-service vehicle that uses only a yaw rate gyro can provide the data needed prioritize track maintenance operations.

This paper investigates the problem of parameter estimation for railway vehicle suspensions so as to provide information to support condition-based (instead of calendar-based) maintenance. A simplified plan view railway vehicle dynamical model is derived and a newly developed Rao–Blackwellized particle filter (RBPF) based method is used for parameter estimation. Computer simulations are carried out to assess and compare the performance of parameter estimation with different sensor configurations as well as the robustness with respect to the uncertainty in the statistics of the random track inputs. The method is then verified practically using real test data from a Coradia Class 175 railway vehicle with only bogie and body mounted sensors, and some preliminary results are presented.

Railway track circuits are used throughout the world as a basic component in safety critical signalling systems to detect the presence of trains. One way to ensure that railways operate with ever increasing levels of availability, reliability, and safety is through the use of intelligent condition monitoring systems to support maintenance activities. This paper presents the results of research on fault detection and diagnosis methods for railway track circuits. The proposed method uses a hybrid quantitative/qualitative technique, known as a neuro-fuzzy system. It is shown that the proposed method has the potential to detect and diagnose the most commonly occurring track circuit failures.

The Enhanced Rail Contribution by Increased Reliability (ERCIR) project aimed to enhance availability by condition monitoring of the track and vehicle suspension from in-service trains. In this project, the possibility of instrumenting an inservice train is explored, with emphasis on using a minimal sensor set for the detection and diagnosis of track and vehicle faults. The use of a bogie-mounted pitch rate gyro to observe mean vertical track geometry is novel, as is using a bogiemounted yaw rate gyro to observe mean lateral alignment as well as the more usual longer wavelength track curvature. Mathematical algorithms are developed to detect vehicle suspension faults and track irregularities. The suspension faults considered are changes in secondary lateral and anti-yaw dampers, and changes in effective conicity. Sudden changes are detected and diagnosed using a Kalman filter-based innovation approach; gradual changes in damping coefficients and effective conicity are detected by parameter estimation usin...

The modeling and simulation of the electrified transit system is an essential element in the design process of a new railway, or an existing one being modernized, particularly in DC powered railway systems which have significant losses in the power network. With the continuing focus on environmental concerns and rising energy prices, energy-saving operation technology for railway systems has been paid more and more attention. Previous work on energy optimization techniques mainly focuses on optimizing driving strategies subject to geographic and physical constraints, and kinematic equations, which only minimizes the mechanical energy consumption without considering the loss from the power supply network. This paper proposes a DC power network modeling technique and extends the traditional energy-saving methods to develop a novel approach which combines traction power supply network calculations and numerical algorithms to minimize the electrical energy delivered from substations. As train resistance is time-varying with the train movement, iterative algorithms are presented in order to calculate the energy consumption dynamically. Some case studies based on the Beijing Yizhuang Subway Line are presented to illustrate the proposed approach for power network simulation and energy-saving, in which the energy consumption of both the practical operation and optimal operation are compared.

Regenerative braking improves the energy efficiency of railway transportation by converting the kinetic energy into the electrical energy. In this paper, Linear Programming (LP) is applied to search for the train braking trajectory with the maximum Regenerative Braking Energy (RBE). LP takes the advantages of simplicity in modelling, efficiency in computation, flexibility in applications. Compared with a previously proposed model, the proposed LP optimisation model takes into account the speed limit constraints during the braking operation. Four case studies have been performed with different speed limits and initial braking speeds. While the maximum allowed braking time takes a key role for the RBE recovery, a threshold exists when the impact of maximum allowed braking time starts to become negligible. It has been demonstrated in this paper that LP is a robust and effective method to locate the optimal braking trajectory with the maximum RBE. The results of the optimisation are of significant interest for urban transportation systems where the regenerative braking is frequently applied. Future work of this paper is to investigate the optimisation of RBE in a more complicated scenario where the gradients are present and the motoring operation of train is allowed.

An inertial measurement unit (IMU) comprising three accelerometers and three gyroscopes all of good quality, attached to the bogie of an in-service railway vehicle and suitably processed in conjunction with a tachometer signal and a GPS feed, tracks the location, orientation and trajectory of the bogie. Using this data, the condition of the track geometry can be assessed. By monitoring this data as the vehicle moves around its normal operating route(s), changes in track geometry can be tracked with a relatively fine granularity in time. The research described here details the uses to which such fine granularity track geometry data could be put, and the development of automated processing to extract the desired information. The aim is to observe track geometry through renewals, degradation and maintenance to understand how faults develop and how effective maintenance has been.

Track circuits form a critical part of the UK rail signalling infrastructure. Condition monitoring of track circuits may improve the availability of track circuits, hence improving service levels. Audio frequency track circuit condition monitoring is a relatively new concept and little work has been done on the subject. This paper describes the instrumentation of a length of active track to observe the variations in track circuit behaviour with environmental fluctuations as well as the effects of Track Circuit Assisters (TCA) on the functionality of the monitored track circuits.

This paper describes the background to, development and trials of a system fitted to in-service train which can measure the quality of the dynamic interface between shoegear and the third rail on the UK 750V DC network. The paper will demonstrate the early results showing the systems ability to pick out locations where the interface is performing abnormally and to detect the defects responsible for those deviations. (5 pages)

The aim of this research is to identify problems at transition zones, also known as critical zones, which are between an open track and a super structure, by means of field monitoring. Data has been collected using vehicle-borne instrumentation, including bogie-mounted inertial sensors. The purpose of this research is to simultaneously measure the vertical displacement of mam" consecutive sleepers by means of sleeper mounted Positional Sensitivity Device (PSD) sensors and geophones connected via a Controlled Area Network (CAN) bus, which enables data transmission among multiple nodes. This paper summarises the initial work carried out with a prototype of the PSD sensor. PSD sensors were tested in the laboratory using different electronic components and fine tuned with a range of central frequencies using a programmable oscillator. In future work the sensor network will be deployed, which can cover up to 16 sleepers in a known critical zone to obtain data during the train passage. In addition, to supplement the constraints of each methodology, comparison tests between the PSD sensor and geophone sensors will be part of future work. (5 pages)

Periodontitis is a prevalent chronic inflammatory disease, a major cause of tooth loss and associates with systemic morbidity and mortality. Biologically, it associates with reduced local and systemic antioxidant defences and elevated levels of oxidative stress secondary to a hyper-inflammatory neutrophil host response to plaque bacteria. This randomised, placebo-controlled, double-blind trial, aimed to assess whether adjunctive benefit could be detected with Juice Plus+® supplementation during and after standard non-surgical periodontal therapy. Primary outcomes were reduction in periodontal pocket depth (PPD) and gain in connective tissue attachment level (CAL) to teeth, 2-months posttherapy. Test interventions were fruit/vegetable (FV, n=16) and FV/berry (FVB, n=15) verses placebo (PL, n=17). Statistical analysis employed 2-tailed ANCOVA (baseline PPD and CAL as covariates) and interim data on 48 never smokers are reported. Non-surgical therapy produced significant improvements in PPD (FV = 0.86±0.4mm; FVB = 0.88±0.4mm; PL = 0.81±0.5mm) and for CAL (p

On a main line railway network with many junctions, this paper describes how the delay of a train is likely to cause delays to many other trains, especially because of conflicts at junctions. Optimizing one junction, however, may have an adverse effect on other parts of the rail network because of the mixed-traffic situation of most main line railways. To approach the complicated problem of optimal re-scheduling in response to the delay of a train, an efficient algorithm must be sought. The authors have taken a junction as an example, and have performed numerical optimization on a case when the services through this junction are disrupted. The objective criterion is the weighted sum of train times. The optimization program uses the Object-Oriented Multi-Train Simulator (OOMTS) developed by Birmingham University, as an embedded simulator. In the optimization routine, a Genetic Algorithm (GA) was used to optimize the order of route setting. In this paper, the authors give details of a model junction, and a brief explanation of the OOMTS. The authors then explain how a GA can be applied to solve this problem, especially the chromosomal expression of the problem. The results of numerical optimizations for different weighting parameters are shown based on which the authors discuss the feasibility of the proposed method.

The development of new simulation software must include validation with real or known data if it is to achieve full credibility. In the case of fully integrated multi train simulators the validation can be complex as it involves verifying both the train movements' parts of the simulator together with the electrification system elements. Multi train simulators can create unreasonable expectations from both users and railway authorities inexperienced with the limitations of simulations. The validating of a Multi Train Simulator serves to demonstrate that the simulator is behaving as expected and to build confidence for the user. Validation is the term given to ensuring that the simulator is providing the results expected and can be carried out through calculation alone but this is unlikely to provide the confidence that is expected by railway authorities. It is often difficult to achieve true and comprehensive validation of multi train simulation software without the co-operation of a railway authority or operator. The challenge of validating a multi train simulator is not made any easier as client and public expectations of new rail transit systems require the railway designers to incorporate more versatile and sophisticated electrified railway and tram networks. This paper seeks to explain the challenge of validating a multi train simulator, including the train movements, electrification system and rail potentials. Additionally the paper will review the technical necessities of validating multi train simulators.

Low voltage DC powered railway systems have significant losses in the power network. This paper presents interim results from a project which aims to measure simultaneously the power output from substations and power input to vehicles. Data have been recorded in initial instrumentation test runs on both a vehicle and two substations. The instrumentation system performed adequately and the quality and accuracy of the data are appropriate to meet the overall objectives of the study. It is possible to see details in the current waveforms, such as notching currents, from the instrumentation located on board the train and at the substations.

Background Occlusal interventions may be used in adults with periodontitis. At present there is little consensus regarding the indications and effectiveness of occlusal interventions in periodontal patients. Objectives To identify and analyse the evidence for the effect of occlusal interventions on adults who have periodontitis in relation to tooth loss, probing depths, clinical attachment level, adverse effects and patient-centred outcomes. Search methods The search was last conducted in April 2008. We searched the Cochrane Oral Health Group's Trials Register (to 30th April 2008); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, Issue 1); MEDLINE (1966 to 30th April 2008); and EMBASE (1980 to 30th April 2008). There were no language restrictions. Selection criteria We included randomised controlled trials (RCTs) assessing occlusal interventions in patients with periodontitis with a follow up of at least 3 months. Data collection and analysis Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in duplicate and independently by two review authors. Any disagreements between the review authors were resolved by discussion. The main investigator of the included trial was contacted to obtain missing information. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis. Main results Abstracts of 54 papers were identified by the search. One paper was eligible for inclusion. This paper studied the effect of occlusal adjustment against no occlusal adjustment in patients who were treated with non-surgical and surgical periodontal therapy. Methodological quality assessment of the included paper revealed that randomisation of the patients into the treatment groups was adequate. Allocation concealment, masking of patients and clinicians were not reported and no response to author contact was received.Mean change in attachment level and mean pocket depth were reported in the included trial. Mean difference in clinical attachment level between occlusal intervention and control in the non-surgical group amounted to 0.38 mm (95% confidence interval (CI) 0.04 to 0.72) favouring the occlusal intervention group and was statistically significant. In the surgical group the mean difference in clinical attachment level between occlusal intervention and control amounted to 0.40 mm (95% CI 0.05 to 0.75) favouring the occlusal intervention group and was also statistically significant. The difference in mean pocket depth reduction between the occlusal intervention and control in both the surgical and non-surgical groups was less than 0.1 mm and was not statistically significant. Tooth loss, patient-centred affects and adverse effects were not reported. Meta-analysis was not possible due to the inclusion of only one study. Authors' conclusions There is only one randomised trial that has addressed this question. The data from this study are inconclusive. We therefore conclude there is no evidence for or against the use of occlusal interventions in clinical practice. This question can only be addressed by adequately powered bias-protected randomised controlled trials.

Railways are expected to operate with ever increasing levels of availability, reliability, safety and security. One way of ensuring high levels of dependability is through the use of condition monitoring systems. This paper presents initial results from operational trials of track circuit condition monitoring equipment installed at two TI21 audio frequency track circuits in the UK.

The mechanical interface between vehicle-mounted shoegear and the third rail is critically important to the smooth running of electrically powered railway vehicles. An investigation is being undertaken into the static and dynamic interactions between shoegear and the third rail. This is being done by instrumenting the shoegear of a class 375 railway vehicle in the UK.

Track recording vehicle equipment has been miniaturised to such an extent that it can be mounted on an in-service vehicle for monitoring track geometry. An alternative approach is to mount a few robust sensors such as accelerometers and rate gyroscopes onto the bogie and axleboxes of an in-service vehicle. The track geometry information that can be obtained from these sensors is incomplete; in particular gauge is unobtainable and data are affected in the lateral direction by the movement of the wheelsets with respect to the track. Nevertheless, estimates of mean vertical and lateral alignment standard deviations and some track geometry faults can be obtained to inform track maintenance. The motion of the bogie and wheelsets with respect to the track, though adversely affecting track geometry reconstruction, may contain valuable information about the interaction between a particular vehicle and the track (or, at least, between the instrumented bogie and the track) that could itself be monitored. This paper illustrates some features observed in the bogie and axlebox obtained from sensors fitted to a Tyne and Wear Metro vehicle that provide information about vehicle/track interaction but do not explicitly reconstruct track geometry.