bluuebunny/crossref_metadata_2025 huggingface dataset:
Techniques for modelling the frequency of explosions on offshore platforms
Authors: Foster K J , Andrews J D
Published: October 2002

This paper describes a scheme by which the explosion frequencies and resulting overpressures can be predicted for modules on an offshore platform. Given a leak of gas, the success and failure of the isolation, blow-down and deluge systems, which are designed to activate following a leak to mitigate the consequences, are considered. The frequency of each possible response to the leak is predicted using a conventional event tree and fault tree approach. Each scenario has a potential escape inventory, which together with the hole size distribution provides the escaping mass flowrate. Once the flowrate into the module is established, the wind conditions are used to determine the gas in air concentration build-up. The concentration profile with respect to time is linked to the ignition source probabilities, from which calculations can be made to assess the likelihood that an explosion will occur within a specific concentration range.

The initial models assume that the gas concentration at any specific time is uniform within the locality of the leak. The work presented in this paper proposes an approach that determines the explosion probability dependent on the volume fraction of gas within the module and the likelihood of encountering an ignition source.
A non-dimensional method to increase the accuracy of turbine flowmeters
Authors: Cuthbert M R , Beck S B M
Published: October 2002

Turbine flowmeters are inherently non-linear at low flowrates. A computer can, however, correct this non-linearity. The most common method of linearization currently used is based on a graph of the K factor (transducer pulses per litre) against the flowrate. This method is only accurate for the fluid properties for which the meter was calibrated. The accuracy deteriorates substantially if oil of a different viscosity, or the same oil at a different temperature, is used. This paper reports a new method of compensating for changes in viscosity over a large range.

Tests on three sizes of flowmeter were carried out, using oil and water. Two dimensionless groups, modifications of the well-known Strouhal and Reynolds numbers, were used to produce plots of the data. The results were shown to compensate for changes in viscosity and also removed some of the underlying dimensional differences between the different turbines. The resulting sixth-order polynomial is used for flowmeters of different sizes, but with a different set of coefficients for each. The final result provides both a more versatile and a more portable method of linearizing turbine flowmeters.
Synergistic classification systems for wood defect identification
Authors: Pham D T , Alcock R J
Published: October 2002

This paper discusses synergistic classification systems (SCSs) for categorizing defects in wood sheets. These systems combine several classifiers to improve the performance achievable with individula classifiers. Different types of classifier could be employed in an SCS. Because of their superior generalization ability, neural classifiers were adopted in preference to rule-based classifiers. The paper describes the tuning of the parameters of the neural classifiers and the determination of the optimum number of classifier units and the best of five strategies for combining their outputs.
Recovery of waste rubber through pulverization at a low temperature of refrigeration by an air turbine
Authors: Wang P , Liu S Y
Published: October 2002

Waste rubber is turned to fine rubber powder of above 60 mesh through freezing and pulverizing at a low temperature by an air turbine with a reflux refrigeration cycle system. The cost of energy consumption for the process is only one tenth of that for the traditional liquid nitrogen freezing and pulverizing process widely used in the world. It is a creative new process for the recovery of waste rubber without any contamination.
Optimizing the design of waveplates for gas-liquid separation
Authors: Wilkinson D
Published: October 2002

Waveplate separators remove liquid sprays from a gas stream by directing it round small-radius bends in narrow ducts. Such separators are generally compact with quite low pressure loss and are effective at removing drops larger than about 5 μm diameter.

The performance of plain waveplate separators has been assessed in terms of the collection efficiency, the pressure loss across the separator and the separator size. Experimental data were correlated using empirical descriptions of waveplate operation based on simple theory and existing correlations for duct flows. Using these relationships, a method to optimize designs of plain waveplate separator in terms of pressure drop has been devised and demonstrated.

It was concluded that the optimum waveplate separator design has three bends of approximately 33°, 66° and 33° with a duct width-side ratio of 0.094 based on experimental measurements made in air-water systems.
Machine condition monitoring for consistent paper production
Authors: Bissessur Y , Martin E B , Morris A J
Published: October 2002

This paper focuses upon the press section of a paper machine and describes a neural network vibration-based condition monitoring system for providing advance warning of faults in the felts. These are extremely important components of the paper machine as they are responsible for guiding the paper through the press nips. Any deterioration in the felts may result in paper breakage and machine shut-downs with a resulting fall in productivity. The need for tighter control of the manufacturing process is thus the main motivation for this work. The system developed makes use of spectral analysis of the raw vibration signals. This involves the technique of acceleration enveloping for isolating the spectral components that reflect the process defects. Since visual examination of the spectra for detecting subtle changes in the early stages is both difficult and impractical, a peak detection algorithm has been designed. Its purpose is to extract the relevant features from each spectrum. These are then fed into a neural network classifier for discriminating between the fault and the no-fault conditions. The system is demonstrated to be successful for detecting felt deterioration in its early stages when assessed on industrial data. Other benefits include the ease of on-line implementation and its possible extension to a wide range of mechanical and rotating equipment.
Condition monitoring of low-speed rotating machinery using stress waves Part 1
Authors: Mba D , Bannister R H , Findlay G E
Published: October 2002

Condition monitoring through the use of vibration analysis is an established and effective technique for detecting the loss of mechanical integrity of a wide range and classification of rotating machinery. Equipment rotating at low rotational speeds presents an increased difficulty to the diagnostician [1-4, 23], since conventional vibration measuring equipment is not capable of measuring the fundamental frequency of operation. Also, component distress at low operational speeds does not necessarily show an obvious change in vibration signature.
A review of creativity principles applied to engineering design
Authors: Thompson G , Lordan M
Published: October 2002

There is a very large amount of literature in the field of creativity outside the field of engineering that has potential for application to engineering design. This paper presents a review of the salient literature and identifies how creativity principles that are based on well-founded research may be applied to engineering design. The scope of the paper includes understanding creativity, creative style, invention and innovation, certain creativity tools and an understanding of the combinations of people, products, creative process and environment that are required to achieve high levels of creativity. A discussion of the application of creativity principles to engineering design is given.
A review of methods to measure and calculate train resistances
Authors: Rochard B P , Schmid F
Published: October 2002

This paper discusses a well-known tool for calculating train resistance to motion and its suitability for describing operations at high speed. The tool, originally developed by Armstrong and Swift [1], also permits the estimation of the contribution to aerodynamic resistance of various features of the architecture of a train. They compare this approach with the results of other formulae for calculating train resistance, as well as published measurements taken during experimental work. It is concluded that Armstrong and Swift's expressions can be considered to provide good estimates for the coefficients to the Davis equation for both high-speed and suburban trains that fit the British loading gauge and have a power car-trailer ratio of 1:3 or less without the need for run-down testing. However, the expressions are not suitable for trains with a predominance of powered axles.
Noise-related roughness of railway wheel treads-full-scale testing of brake blocks
Authors: Petersson M
Published: October 2002

Results from full-scale tread braking experiments on an inertia dynamometer (brake testing machine) are presented. Eighteen prototypes of brake blocks are investigated. Two braking characteristics relating to the influence of the blocks on the wheel tread are studied: generation of hot spots and generation of roughness (corrugation, waviness). Wheel tread temperatures are measured during braking using an infrared (IR) technique. The wheel roughness is measured after each brake cycle when the wheel has cooled down. A roughness indicator, RλCA, relates measured roughness to expected rolling noise as generated by the wheel in operation. A correlation between the spatial distributions of temperatures and roughnesses is normally found: stronger for cast iron blocks and composition blocks and weaker for sinter blocks. The cast iron blocks are found to produce high tread roughness levels, partly owing to material transfer from brake block to wheel tread. The composition blocks are found to result in lower roughness levels than the cast iron blocks. Finally, the sinter metal blocks are found to lead to the lowest roughness levels, a fact which is probably due to the abrasive property of these blocks. Friction coefficients during braking are also measured.
JR East takes up the challenge of ‘searching for a railway that is kinder to the Earth’
Authors: Kamata S
Published: October 2002

Although the railways are said to be kind to the environment, they do consume energy and emit carbon dioxides. They must make it their own responsibility to work ceaselessly at further reducing these effects. The most important point in this respect is whether the railway companies have established a means in management for tackling the problem of improving the environment independently and continuously. In Japan, railways have been an important part of Japan's transport system. In 1994, JR East started up the Committee of Ecology and decided on three basic policies. Great strides have been made, for example, with the environment management system, energy-saving efforts, the movement to grow forests and the reduction in rubbish. It should become increasingly important to have firm strategies for this field in the future, especially in the twenty first century which is being called the ‘environment century’.
Talgo automatic gauge change system for freight wagons
Authors: Gomez J L Lopez , Aísa J Lacasta
Published: October 2002

Between 1970 and 1995, road freight transport in Europe increased by 150 per cent. Existing road infrastructures are saturated, and the environmental impact is enormous. The best solution is to promote international rail freight transport, but the efforts of the European Union to solve the bureaucratic problems at borders are not sufficient. The efficiency of the railways has to be increased, and therefore interoperability problems between the different networks have to be solved. Talgo has designed an automatic gauge change system that allows the transit of freight wagons on networks with different gauges without interruption of the journey or transfer of the freight. The first advance, demonstrating the importance of railways as an efficient means of transportation for freight, is already available. This article includes a technical description of the automatic gauge change system as well as the test carried out for its approval process.
Contact mechanics analysis of measured wheel-rail profiles using the finite element method
Authors: Telliskivi T , Olofsson U
Published: October 2002

A tool has been developed for contact mechanics analysis of the wheel-rail contact. Using measurements of wheel and rail profiles as input, the tool is based on the finite element (FE) code ANSYS. Traditionally, two methods have been used to investigate the rail-wheel contact, namely Hertz's analytical method and Kalker's software program Contact. Both are based on the half-space assumption as well as on a linear-elastic material model. The half-space assumption puts geometrical limitations on the contact. This means that the significant dimensions of the contact area must be small compared with the relative radii of the curvature of each body. Especially in the gauge corner of the rail profile, the half-space assumption is questionable since the contact radius here can be as small as 10 mm. By using the FE method (FEM) the user is not limited by these two assumptions. The profile measurement system Miniprof was used to measure the wheel and rail profiles that were used as input when generating the FE mesh.

As a test case, a sharp curve (303 m radius) in a unidirectional commuter train track used by X1 and X10 trains was chosen. The results of two contact cases were compared with the results of the Hertz analytical method and the program Contact. In the first contact case the wheel was in contact with the rail gauge corner. In the second case the wheel was in contact with the rail head. In both contact cases Hertz and Contact presented very similar results for the maximum contact pressure. For the first contact case, a significant difference was found between the FE method and the Hertz method and the program Contact in all of output data. The Hertz and Contact methods both presented a maximum contact pressure that was three times larger (around 3 GPa) than the FE solution. Here, the difference was probably due to the combination of both the half-space assumption and the elastic-plastic material model. For the second contact case, there was no significant difference between the maximum contact pressure results of the three different contact mechanics methods employed.
Dynamic effects of vehicles on tracks in the case of raising train speeds
Authors: Zhai W. M. , Wang Q. C. , Lu Z. W. , Wu X. S.
Published: October 2002

In order to enhance the efficiency of railway transportation, Chinese Railways has decided to raise the speed of trains on the existing railway main lines. A theoretical model and the corresponding simulation software, VICT, based on the vehicle-track coupling dynamics are employed to analyse dynamic effects of trains on track structures caused by raising train speeds. Chinese passenger cars and freight cars running on the lines where speed has been raised were chosen for investigation. It is shown that raising train speeds on the existing railway lines obviously intensifies the dynamic effects of vehicles on tracks, especially in the turnouts, in the welded rail joints, and in the sections of bridge-subgrade connections. The occurrence of wheel flats becomes more general after raising train speeds. An unfavourable peak of dynamic effects of wheel flats on tracks is observed in the speed range from 140 to 160 km/h, which is just the region of running speeds for passenger trains after the increase in the speed. Some basic countermeasures, including stricter maintenance standards for the speed-raised railways, are proposed to solve these problems, on the basis of dynamic analysis.
Metro traffic regulation from the passenger perspective
Authors: Goodman C. J. , Murata S
Published: October 2002

Maintaining metro ridership in the future will require an increasing focus on customer perceptions of the service quality. This work outlines a process whereby passenger expectations may be encapsulated into a mathematical evaluation function that can then be used in an on-line optimization procedure. The function proposed penalizes excess waiting time, travelling time and congestion following a disturbance such as a platform delay. With the function defined, the problem resolves into finding a set of optimum arrival and departure times (the decision variables) that minimizes this penalty function. Ultimately, the concept is intended to form part of an on-line, real-time traffic controller residing on the despatching computer in a control centre. An embedded simulation is used to perform the optimization calculations, and several techniques are described that reduce the computing time needed to a level feasible for on-line use. Comparisons are made with some previous control algorithms. Using data based on the Hong Kong Island Line, it is shown that the new controller performs well, albeit when using the newly proposed evaluation function as the test criterion.
An analysis of the development of the tramway/light rail concept in the British Isles
Authors: Souter I. A.
Published: October 2002

During the first quarter of the twentieth century the electric tramcar was the dominant mode of local transport in the urban areas of this country. Thereafter, this position was ceded such that by the 1960s tramways had practically disappeared, a rate well in advance of experience elsewhere. Interest in light rail reappeared in the 1970s and six new systems are now in service.

The first stage of tramway decline was brought about by the continual loss of revenue to service a variety of statutory and planning obligations imposed on operators. The second stage came in the 1920s when financially weakened operators had to renew assets in a climate of changing transport demands and economic conditions. Increasingly, as roads and road vehicle technology improved and population spread, the cost-effective option was to convert to motorbus or trolleybus.

The transfer of learning from first generation tramways has been minimal and conditions for light rail development remain difficult although the government is becoming more interested. The easing of legislation governing establishment and operation of light rail services is essential for future expansion, and will be best achieved by the industry finding a voice to speak with authority on its behalf.
Phototube sensor for monitoring the quality of current collection on overhead electrified railways
Authors: Bruno O , Landi A , Papi M , Sani L
Published: October 2002

A new measurement system able to detect the occurrence of arcing between the pantograph and the overhead contact line was studied and set up. The system uses photomultiplier tubes to measure the duration of the ultraviolet emission due to electric arcing. The major advantages of the system proposed are its non-invasivity with respect to the pantograph equipment, its reliability and its low cost. Correlation with data acquired during high-speed test runs from different sensors (e.g. currents measured in an equipotential wire between the front and the rear pantographs, images acquired from a TV camera), provided the opportunity to perform an efficient calibration and an analysis of selectivity of the phototube sensor.

Data from the phototube sensor along with various other information lead to the definition of a reliable index for evaluating the quality of the current collection. The determination of such an index has primary relevance for maintenance activities, for computing the minimal thrusts to be applied to the pantograph at different speeds and for testing new materials for overhead contact wires and collector strips.
The tram-train: State of the art
Authors: Novales M , Orro A , Bugarin M. R.
Published: October 2002

In response to the demand for improved mobility in metropolitan areas, the 1990s saw the development in Europe of a new transport system known as the tram-train. This system is based on the use of conventional railway lines with a low traffic density in order to extend urban tram or light rail services without the need to change vehicle, incorporating them into railway traffic. This allows for a wider range and scope of direct transport services and reduces waiting times and changes. The operation of light rail vehicles on conventional railway infrastructure involves finding solutions to a number of technical issues such as traction power supply system, rolling stock design, gauge, tyre and rail profile, structural strength, passenger access, signalling, etc. This paper describes these problems and the solutions arrived at by services currently in operation, or in advanced planning stages, worldwide.
Shared track—A new dawn?
Authors: Griffin T
Published: October 2002

Shared track is now a possibility in the United Kingdom; the Sunderland Metro will introduce lightweight vehicles on to the Railtrack network. On the other hand, some cities that pioneered the concept are now developing systems where light rapid transit (LRT) and heavy rail are kept separate. This paper examines the technical issues behind these developments. It also examines the scope in the United Kingdom for the wider applications being seen elsewhere in Europe.

Innovative approaches are essential if rail systems are to continue to play a role in short distance passenger transport. Shared track could merge the best of heavy rail and tramway practice to create extremely attractive services, taking advantage of new traction options. The main technical challenge is to create vehicles that are both commercially attractive and meet the safety requirements that apply on those parts of the various systems where they might operate.
Use of multiobjective genetic algorithms to optimize inter-vehicle active suspensions
Authors: Mei T. X. , Goodall R. M.
Published: October 2002

This paper studies inter-vehicle active suspensions for railway vehicles and presents an optimization process for the design of vertical active suspension controllers using multiobjective genetic algorithms. A three-vehicle train set is used in the study and two active control schemes are considered primarily to provide the best improvement in the passenger ride quality. The first scheme uses only actuators placed between adjacent vehicles while the second adds two actuators between bogie and vehicle body at either end of the train set in addition to the inter-vehicle actuators. The development of the control laws is assisted by the use of genetic algorithms to achieve the ‘best’ compromise of different design criteria, especially that between the ride quality and the suspension deflections. The study shows that, when the control laws for the proposed active schemes are optimized, a significant improvement in the vertical ride quality on random tracks is obtained and in the mean time the suspension deflections can be kept within their allowed clearance when the vehicles run on to a gradient.
Speed and rolling stock of trains in fatal accidents on Britain's main line railways: 1967-2000
Authors: Evans A. W.
Published: October 2002

This paper extends the author's earlier statistical analyses of fatal train accidents on the national railway system of Great Britain to include data on speeds and further data on the rolling stock of the trains involved in the accidents. The objective is to explore whether such information is useful in improving projections of fatalities. It is found that the mean number of fatalities in accidents involving loaded or empty passenger trains does indeed rise with impact speed, with different estimated relationships for multiple unit and locomotive hauled passenger stock. However, the actual numbers of fatalities in individual accidents are very variable. An unexpected finding is that there has been only a slight upward trend over time in the mean speeds of trains in accidents; therefore there is no strong reason to expect increased mean fatalities on this account. A direct estimate of the trend in mean fatalities per accident over time shows that this has been almost flat; for that reason the author's preferred projection is now to assume that mean fatalities per accident will remain constant at the overall mean in the data, currently 4.0. This gives projections about 10 per cent higher than the author's most recent previous projections.
US rail equipment crashworthiness standards
Authors: Tyrell D. C.
Published: October 2002

In 1999 the US Department of Transportation's Federal Railroad Administration (FRA) issued new regulations and the American Public Transportation Association (APTA) issued new standards for rail passenger equipment crashworthiness. These new regulations and standards include conventional strength-based requirements for equipment used below 200km/h (125 mile/h), crashenergy management for equipment used above 200km/h (125 mile/h) and dynamic sled testing of occupant seats.
Industrial fault diagnosis: Pneumatic train door case study
Authors: Lehrasab N , Dassanayake H. P. B. , Roberts C , Fararooy S , Goodman C. J.
Published: October 2002

A practical, robust method of fault detection and diagnosis of a class of pneumatic train door commonly found in rapid transit systems is presented. The methodology followed is intended to be applied within a practical system where computation is distributed across a local data network for economic reasons. The health of the system is ascertained by extracting features from the trajectory profiles of the train door. This is incorporated into a low-level fault detection scheme, which relies upon using simple parity equations. Detailed diagnostics are carried out once a fault has been detected; for this purpose neural network models are utilized. This method of detection and diagnosis is implemented in a distributed architecture resulting in a practical, low-cost industrial solution. It is feasible to integrate the results of the diagnosis process directly into an operator's maintenance information system (MIS), thus producing a proactive maintenance regime.
Can railways compete with roads?
Authors: Hardy D. J.
Published: October 2002

This paper looks at the competitive situation between rail and road transport. The economic structure and physical characteristics of both systems are examined. It is shown that it will be extremely difficult to make the railways really competitive without very great changes to both the regulation and the physical characteristics of the railway system. Some ideas on the form that these could take are given in the final part of the paper.
A statistical analysis of fatal collisions and derailments of passenger trains on British Railways: 1967-1996
Authors: Evans A. W.
Published: October 2002

This paper presents a statistical analysis of collisions and derailments involving loaded or empty passenger trains on British Railways in the 30 year period 1967 to 1996 that resulted in fatalities to train occupants. The main conclusions are that there has been a long-term fall of about 4 per cent per year in the accident rate, from about three accidents to one accident per 20 billion passenger-miles between the start and the end of the period; that there is no significant difference in the accident rates of Mark 1 and post-Mark 1 passenger rolling stock; but that post-Mark 1 stock has significantly fewer fatalities per accident than Mark 1 stock. Estimates are made of the average savings in casualties that could be expected from further withdrawals of Mark 1 stock.
Study on passenger train vehicle fires
Authors: Chow W. K.
Published: October 2002

The fire aspects of passenger train vehicles for two of the railway lines (labelled as A and B) in Hong Kong are discussed. Train compartments of railway line A are of enclosed construction whereas vehicles in railway line B are opened to each other. Reference is made to the smoke filling process as this is identified to be the most important aspect in a fire. Simulations with the fire model ASET were performed in train vehicles for railway line A to study the probable smoke temperature and smoke layer interface height for different fires. The fire zone model CFAST and the CORRIDOR menu of the fire protection engineers' tool FPEtool are used to study the fire environment in the train vehicles for railway line B. Results confirmed that smoke is the key factor to consider. Recommendations for providing better fire protection design and fire safety management are made.
Fiat Pendolino: Developments, experiences and perspectives
Authors: Elia A
Published: October 2002

The objective in introducing tilting systems for passenger trains is to optimize the service, shortening travel time and improving comfort, while making minimum alterations to existing track layouts and service conditions. The development of the Pendolino system is described in this paper, starting from early tests on bogies and on tilting systems. The author then describes the extensive service experience of Fiat, with more than 50 million train-km produced and 100 trainsets in service or under construction for service in European countries. An outline is presented of current developments and the product strategy, together with a description of available R&D prediction/measuring tools.
The bogie-based tilt option-simplicity and flexibility
Authors: Huber B. H.
Published: October 2002

The development of the bogies and the electromechanical tilting system, which has been chosen by the Swiss Federal Railways for their new InterCity tilting trains, is described. These trains will start to enter revenue service in 1999.
Control system studies of an active anti-roll bar tilt system for railway vehicles
Authors: Pearson J. T. , Goodall R. M. , Pratt I
Published: October 2002

This paper describes a theoretical study of an active anti-roll bar tilt control system for a railway vehicle. It presents the rationale behind body tilting, the advantages and disadvantages associated with body tilting and the key tilt control system requirements. The paper also describes the control modelling process and presents some simulation results from control system studies. A number of competing control systems have been designed and analysed, including both classical and optimal control strategies. The performance of the control systems for a variety of curves is considered, as well as their response to track irregularities. The results show that all the strategies provide good tilting performance, the optimal control approach being marginally better.
Research trends on riding comfort evaluation in Japan
Authors: Suzuki H
Published: October 2002

To make railways a more comfortable means of transport, it is essential to improve riding comfort. The concept of riding comfort is related to two categories of measurement. One is the measurement of physical quantities that affect riding comfort and the other is the measurement of the corresponding feeling of human beings. Although various evaluation scales have been proposed, an evaluation criterion universally applicable has not been established yet. To encourage discussions on the evaluation of riding comfort of railway vehicles, this paper reviews relevant researches carried out in Japan. Topics covered include features of riding comfort of railway vehicles, vibrational characteristics that affect riding comfort, momentary and long-term vibration, riding comfort criteria in Japan, response indices to riding comfort and motion sickness experienced on railway vehicles.
Anything but boring
Authors: Etwell M. W. J.
Published: October 2002

The author reflects on a railway career encompassing development of men and machines through maintenance and design to management of engineering projects in both freight and passenger applications.
The privatization of British Rail 1994-1997
Authors: Godward E
Published: October 2002

This paper examines the privatization of British Rail between 1994 and 1997. The transition from one public sector organization to many private sector companies is examined with the objective of understanding the impacts of privatization. Using the latest available data, an attempt is made at understanding the costs and benefits of the process. The new structure and organizations within the industry are explained and examples are given of the progress and developments being made. Some emerging issues that are a direct result of the process are touched upon.
The developing relations between science, technology and the railways
Authors: Russell C. A.
Published: October 2002

While it is very clear that the railway industry from the very beginning owed an immense debt to the disciplines of civil and mechanical engineering, it is far less obvious that the sciences as such had any major contributions to make. This is partly because of a common confusion as to the nature of science and technology and of their relationship together, but chiefly it arises from the fact that very little historical research has been carried out on the topic. Nevertheless some broad outlines of the problem have now become clear. One important element in the situation is the very distinctive kind of response made by the railway industry in its early days and far beyond. Its tendency to be derivative, empirical, interlocking, labour-intensive and acutely aware of public attitudes lasted long into the twentieth century and profoundly affected its development. So also did the way it responded to constraints associated with cost, environment and what can only be called ideology. The one science that unquestionably made a major contribution was chemistry, from the first halting attempts to assess the quality of boiler feed water, through the establishment of laboratories by many of the pre-grouping companies, to the most recent and diverse studies at Derby and elsewhere. It was the first of what may properly be called ‘the railway sciences’.
A parametric study of the lateral stability of a rail bogie on a roller rig
Authors: Dukkipati R. V.
Published: October 2002

The development of experimental facilities for rail vehicle testing is being complemented by analytical studies. The purpose of this effort has been to gain insight into the dynamics of rail vehicles in order to guide the development of roller rigs and to establish an analytical framework for the design and interpretation of tests to be conducted on roller rigs. The work described here represents an initial effort towards meeting these objectives. Parametric study results using a linear model of a freight bogie on a roller rig showed that:
Vertical transportation in modern metro stations
Authors: Horgan D. J.
Published: October 2002

This paper will briefly discuss vertical transportation in modern metro stations. The selected stations for review are London Underground Limited's Jubilee Line Extension, United Kingdom, and the Land Transport Authority's North East Line, Singapore. The discussion will include modes of vertical transportation, planning and provision of vertical transportation, design life and technical specifications, capital and whole life cycle cost. The paper concludes that modern metro stations use a large number of escalators to transport passengers through the stations which are complimented by a lift service for physically impaired passengers and those with heavy luggage or pushchairs.
Inviscid fluid flow around high-speed trains passing by in open air
Authors: Reinhardt-Piéchowiak A , Ducruet C
Published: October 2002

Aerodynamic effects during high-speed train running must be evaluated in order to avoid safety and comfort problems. This becomes all the more important as cruising speed increases. Risks are also greater in the case of trains passing by each other. However, experimental fittings adapted to the investigation of train passing-by and experimentations on real track lines are complicated and very expensive. A numerical investigation was attempted in order to evaluate unstationary forces on trains in open air regarded as an inviscid fluid. A computer code was developed on the basis of a singularity method: it includes possible compressibility and wake effects. Results were obtained concerning local and global aerodynamic loads acting on trains passing by each other.
Noise from railway bridges
Authors: Hardy A. E. J.
Published: October 2002

Although it has long been recognized that when a train passes over a bridge there is frequently an increase in noise levels, accurate prediction of this phenomenon is often neglected. Using a modified version of AEA Technology Rail's ‘re-radiated noise’ model and data on existing bridges, this paper shows how the noise from a bridge can be predicted. In addition, the paper considers how the noise from bridges can be predicted using statistical energy analysis, and shows that reducing the vibrational input or providing baffles around the structure is likely to be the most effective way of reducing the noise from a bridge.
Train-generated sound within an underground light railway system
Authors: Lilley D. M.
Published: October 2002

An empirical study has been made to identify important features of sound levels generated within an underground section of a light railway. Measurements of sound pressure level were recorded as trains passed within a few metres of computer-controlled instrumentation during normal daytime operation. Peak values of sound pressure level were identified for each passing train and a method of compensating for train speed was investigated. Further measurements were taken of sound levels as two Metro trains were repeatedly driven through the same section of underground track at different nominal speeds during a night-time possession.

Characteristics of sound levels produced by approaching and departing trains have been studied to identify any salient features that may be beneficial in developing a means of monitoring the condition of passing trains. No definitive relationship was identified between train speed and peak value of sound pressure level, although results indicated that higher sound exposure levels and duration when a passing train generates sound levels above a threshold value can be linked to train condition. Further development of the work is planned to provide an automated management tool for identifying trains in need of further inspection and maintenance. The ultimate aim is to improve the efficiency of scheduling for train maintenance and to satisfy environmental needs for keeping train-generated sound to minimum levels.
Enhancing freight railways for 30 tonne axle loads
Authors: Nielsen J. C. O. , Stensson A
Published: October 2002

An effective approach to decrease railway transportation costs is to invest in higher axle load and higher speed. Following a query from the Swedish iron-ore mining company LKAB, the railway infrastructure authorities of Banverket in Sweden and Jernbaneverket in Norway initiated a study of consequences and costs for an upgrading of axle loads from 25 to 30 tonnes (t) on Malmbanan and Ofotbanen. The influence of increased axle loads and improved bogie design on track structure degradation and costs for maintenance and reinvestments has been investigated. Full-scale field measurements of wheel-rail contact forces for the present iron-ore wagons with 25 t axle loads and for two types of prototype wagon with axle loads of 30 t have been performed. Computer simulations of dynamic wagon-track interaction and literature studies also provided information used in the estimation of track degradation rates. The total cost for upgrading the infrastructure to take 30 t axle loads was found to be lower than anticipated. As a consequence, five prototype wagons dimensioned for 30 t axle loads and radial self-steering bogies of the Scheffel HS type have been ordered and were delivered in early 1999 for tests on Malmbanan-Ofotbanen.
Aerodynamic and structural design of a solar-powered micro unmanned air vehicle
Authors: Wilson C , Nutbean J , Bond I
Published: October 2002

The field of micro unmanned aerial vehicles ((μUAVs) has advanced rapidly in recent years. This paper studies the design and construction of a small solar-powered aircraft near the size range of current (μUAVs. A number of aspects of their design were analysed, including structural, aerodynamic and propulsion system considerations. The effect of small-scale, low Reynolds number aerodynamics was investigated, and the performance of a range of candidate aerofoils was compared. The integration of a solar power source into the aircraft system was considered a key design issue. Consequently, a number of aircraft configurations were examined, with the intention of optimizing the application of solar power in a miniature aircraft. Investigation of improved system components suggests that a practical solar-powered aircraft in the size range below 500 mm maximum linear dimension should be viable given modest technological improvements.
Fast boundary layer suction optimization with neural networks
Authors: Wright M C M , Nelson P A
Published: October 2002

Previous experiments on a flat plate with four suction panels in a wind tunnel have shown that it is possible to optimize the distribution of suction so as to minimize the suction energy required to maintain laminar-turbulent transition at a fixed position. The location of the transition can be detected by surface-mounted microphones. This can form the basis of a ‘smart suction’ system which can adaptively minimize energy consumption in flight. The gradient descent optimization scheme previously employed finite difference estimates of the gradient of transition position as a function of the suction velocity at each of the panels. This is slow if the number of suction panels is large. It is shown that the optimization can be made considerably faster if the suction-transition function is pre-identified using a radial basis function neural network. Because of the robustness of the optimization algorithm to the gradient estimate, the number of measurements needed to pre-identify this function is surprisingly small, in the present case 3 N, where N is the number of suction panels.
Aircraft pitch and heave rate control
Authors: Whalley R , Ebrahimi M
Published: October 2002

The dynamic model of a high-performance military aircraft is considered. An input-output representation relating the open-loop pitch and heave rate characteristics to elevator movement is derived. Effective closed-loop design techniques are invoked. Simulated response transients are presented.
Dynamics of nose cone jettisoning from spinning rockets
Authors: Babu K K R , Lochan R
Published: October 2002

The jettisoning of a nose cone in space from a spinning rocket has been investigated. The spring-assisted separation system is described with its mathematical model. The resulting non-linear equations have been integrated numerically. The geometry for safe separation has been analysed and the influences of various imperfections in the system, such as dynamic asymmetry, dynamic imbalance, separation system imperfection, etc., are studied. The analysis presented here enables a clear understanding to be obtained of the separation dynamics of a nose cone in a spinning environment. A closed-form solution has been obtained for the relative motion between the separating dynamically symmetric bodies devoid of any dynamic imbalance under the influence of a perfect separation system. For the same system, simple design formulae have also been derived for collision avoidance, which can be gainfully utilized for initial sizing of separation systems.
The bending of composite shallow revolutional shells
Authors: Ye Z , Zhou Z
Published: October 2002

This paper deals with the bending problem of composite revolutional shells under the action of distributed loading using a new approach, the non-orthogonal series method, i.e. NOSM. The formulation is based on the thin shell theory of small strains. The basic equations are developed and can be expressed in matrix form for composite revolutional shells. In general, because of the anisotropic characteristics, there will be a coupling effect in the boundary conditions, even including the axisymmetrical bending case. The non-orthogonal function series adopted showed very significant coupling effects in such anisotropic and orthotropic revolutional shells. Finally, a composite shallow spherical shell was investigated and the results show that the coupling effect at the boundary conditions makes the maximum displacement smaller than in the case of no coupling.
Transition detection for laminar flow aircraft using microphones beneath the surface of laser drilled suction panels
Authors: Barrett R V
Published: October 2002

The possibility of detecting transition through the very small laser drilled perforations in panels representing the suction surface of a hybrid laminar flow aircraft is examined. The method uses miniature microphones to detect changes to the noise received from the boundary layer. Tests using a flat plate rig in a low-turbulence wind tunnel at Reynolds numbers up to 3.8 million per metre, demonstrate that the boundary layer state can be defined in this manner, most simply through measurement of the root mean square (r.m.s.) of the microphone signal. It is shown that the r.m.s. reaches a peak in the transition zone and that when the boundary layer is fully turbulent the value is still significantly higher than it was before transition. Porosity in the range 0.8-6.4 percent was examined, with nominal hole diameters of 0.06 and 0.10 mm in 0.9 mm thick laser drilled suction surface specimens. Suction flow through the surface was found not adversely to affect the operation of the system.

The experiment was limited to low Reynolds numbers because the high background noise in the wind tunnel made detection of the boundary layer element of the signal increasingly difficult to define as speed increased. It is considered that test in flight will be needed to prove fully the validity of the method. A preliminary design of an installation for this purpose is suggested that allows the suction flow to be maintained over the measuring region.
A quasi-three-stage space-qualified passive radiator system for cooling a detector array to −150°C
Authors: Butler I G , Goodall C V
Published: October 2002

The necessity for cooling to temperatures less than −100°C has become increasingly common as the sensitivity of detectors used in space has improved. This temperature range is outside the reach of a single radiator, so active coolers or more complex multiple radiator systems are needed. This paper discusses the advantages of using a multiple passive radiator system and explains the rationale behind the design of such a radiator system. To show how a multiple radiator system can be used in practice, the experience gained from producing the radiator system for the EPIC MOS camera head on the XMM spacecraft. This radiator subsystem consists of three conical radiators, forming a quasi-three-stage radiator system, which is completely removable from the camera head. The significant advantages of using conical radiators are explained, and the detailed thermal model and testing of this radiator system are presented. The validity of this design was demonstrated during a thermal balance test of the full camera head that achieved a charge coupled device (CCD) temperature of −150°C. Finally, the sensitivity of the radiator design to degradation of the thermal finishes and the ways in which the radiator system could have been optimized are discussed.