Independently Rotating Wheel Systems for Railway Vehicles-A State of the Art Review

This paper surveys the state-of-the-art in the field of Independently Rotating Wheel systems (IRW) for railway vehicles. Various methods that have been adopted to provide guidance capability to the system are discussed. Results of the stability and response characteristics of such systems obtained through both experimental and analytical efforts by various researchers are reviewed. Some critical research needs are identified.     

Forecasting transport development: Testing the utility of a simple regression approach

The analysis tests the utility of a simple regression approach in postdictively explaining transport development in West Malaysia from 1887 to 1968. The growth of the network is modelled as a process of contagious diffusion where transport densities of adjacent cells are used as predictor variables on a lagged basis. The partial regression coefficients provide measures of network orientation over time. The results demonstrate the importance of the contagion process in transport forecasting and provide equivalent levels of explanation when compared with a model which utilizes modernization indexes as predictor weights.I am grateful to Peter Gould for his advice and suggestions in the early stages of the research and for the comments of Peter Haggett, Mark Monmonier and J. Barry Riddell, all of whom read drafts of the paper. I also wish to acknowledge the financial support provided by a University of Vermont Faculty Fellowship.     

Level of public transport service evaluation: A fuzzy set approach

The success of any enterprise, in a market-oriented economy, depends upon it's quality. This paper describes the results of a survey of commuters on the quality of services and their relative weights, and of the attributes that determine the service level of bus transport undertakings. The model uses the theory of fuzzy sets to process the information obtained. A composite index, called level-of-public transport-service (LOPTS), is defined and used to measure the service qualities. This approach is presented with guidelines for rating the quality of services, fuzzy-set representations of the linguistic grades, definition of LOPTS and its use in a public transport quality data base. An example is presents how the approach can be employed to analyse data bases generated from a quality survey. This approach is compared with the numerical rating approach with single number representation.     

Full scale measurements at magnus

The environmental and structural monitoring system on Magnus tower was designed making use of experience from previous monitoring systems on West Sole, Forties and Buchan. The paper describes the measuring systems adopted together with their calibration procedures and independent checks.

The major results in terms of environmental conditions and platform response are discussed. They are compared with the Forties results and standard design procedures. Deterministic and spectral extreme conditions are considered. Where applicable, comparisons are made with other published results.

Finally, the principal conclusions of the measurement programme are presented and discussed. These refer particularly to structural dynamics, coefficients for the Morison equation and appropriate methods of application of wave loading to a deep water structure.     

Time series for sea water and seaweed of Tc and Sb originating from releases at La Hague

⁹⁹Tc and ¹²⁵Sb have been released in low level liquid waste at the reprocessing plant at La Hague (Fr). Over a number of years data have been obtained on the concentration of ⁹⁹Tc in sea water and in seaweed from sampling locations close to and at increasing distances north and east of the point of release into the English Channel.In addition such data have been obtained on ¹²⁵Sb for a small number of sampling points. These time series, and the information derived from their intercomparison and from comparison with the release data, are presented in this paper.Time series on ⁹⁹Tc as well as ¹²⁵Sb in sea water and seaweed clearly confirm a considerable decrease in release rates at La Hague over the years 1986–1993. Transit times and transfer factors derived from the series are generally in good agreement with the results of modelling efforts. The data do not provide evidence for a time lag between levels of the radionuclides in sea water and those in seaweed longer than a few months.The very high concentration factors for ⁹⁹Tc in brown seaweeds make these seaweeds very useful for environmental monitoring the radionuclide at low release rates and to trace releases in areas remote from the point of release.     

Analysis of the Stability of Braking Systems in Car and Caravan Combination

In the present article, a mathematical model of the car-caravan combination has been constructed. In simulating the transmission of forces in the articulation of the joint, special attention has been focussed on two types of action in the braking system of the caravan: the conventional braking through overrun and a prototype with hydraulic action. The model of the articulation has been compared with tests carried out on a real vehicle. This model has been constructed by means of a computer programme with different braking maneuvers with the view to analyse the influence of one system or the other on the general behaviour of the vehicle.     

The Dynamics of Single Track Vehicles

The paper contains a brief review of the more subjective aspects of the steering behaviour of single track vehicles, a review of the more significant published work in the field, and an assessment of the current state of understanding and likely ways in which further progress can be made

Attention is drawn to the many areas of agreement between theory and practice and to some areas of disagreement. The greatest need now seems to be for the incorporation of more complex tyre models into vehicle handling models.