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Practical railway engineering. Introduction


Practical railway engineering. Introduction


Clifford F Bonnett

Preface

The need for this textbook arose originally in 1994 out of the author’s experience whilst co-ordinating the optional subject ‘Railway Engineering Concepts’ for the Intercollegiate MSc Course in Transport run jointly by Imperial College and University College, London University.

The stated objective of this optional subject is:

‘To develop an understanding of the engineering concepts involved, for all disciplines, in the planning, design, constructionn, equipping, maintenance and renewal of all types of railway. ’

The author quickly discovered that there were many textbooks which gave detailed information on various aspects of railway engineering, usually confined to one or two main disciples, but none that provided a general ‘broad brush’ approach to the subject as a whole.

The first edition of this textbook was published in 1996 and was specifically designed to fill this gap, not only for the student on this or similar courses, but also to be a useful reference book to all who need to expand their knowledge in this wide field. The first edition was adopted as a standard textbook by a number of Universities and Colleges. Although the basic principles of such a subject do not change over time, some of the details of the book needed up-dating and this has been the author’s objective in producing the second edition.

The author wishes to acknowledge extensive help he has received from many practicing engineers and, in particular, those who regularly have contributed lectures on this subject to students on the London University course. In addition thanks are recorded for comments received on the first edition which have been taken into account in producing the second edition. One of the main changes in the second edition is the improvement of the illustrations and the introduction of some colour prints, made possible by the publishers, which is much appreciated.

Acknowledgements

The author wishes to express his thanks to the Professors, lecturers and staff of the Centre for Transport Studies of the University of London for practical help given in the production of this textbook.

In particular he would also wish to record thanks to the following external lecturers who have assisted with material outside his own railway practical experience:

Eddie Goddard Chris Hardie Chris Holmes Dr. John Medhurst Terry Mahoney

Appreciation is also expressed to Paul Walker for general railway advice and interest during the production of the second edition and in providing a number of the colour photographs, which are suitably acknowledged in the figure titles. Thanks are also due to Network Rail, London Underground Ltd, Docklands Light Railway Ltd, The Science Museum, the Institution of Railway Signal Engineers and the Permanent Way Institution for assistance with the gathering of facts, information and illustrations.

I am particularly grateful to Professor Tony Ridley who has been a great encourager during the writing of both editions and for providing the Foreword.

Introduction


1.1 Early Beginnings

In medieval times people mostly travelled by foot or horseback and any form of transportation was mainly for moving goods.

The first railways were laid down in the seventeenth and eighteenth century for horse drawn trains of wagons in collieries and quarries. These ‘hauling ways’ initially had a surface of stone slabs or timber baulks, which soon proved unsatisfactory as the loads carried inevitably grew heavier.

As the Industrial Revolution progressed, the idea was developed further by adding cast iron or wrought iron plates to reduce wear on the wooden baulks. This evolved further to iron edge rails enabling the use of flanged wheels for the first time.

By the time steam locomotives came on the scene, in the early nineteenth century, wrought iron rails and later steel rails were developed which were strong enough to support these heavy axle loads without assistance from longitudinal timbers.

In essence the track itself, together with its supports, had and still has the basic function of safely transmitting the loads and forces imposed by passing trains to the ground beneath.

Various other civil engineering skills were also involved in the construction of early railways.

These included the building of bridges, tunnels and gravity walls as well as extensive earthworks and drainage.

From these earliest days, there was a need to balance the requirements and interests of the various engineering disciplines involved. As an example, rolling stock design has a considerable impact on the design and maintenance of the fixed infrastructure and there needs to be mutual appreciation and close co-operation between engineers if the best is to be achieved in all areas. This may sometimes require compromise in certain disciplines for the good of the whole.

1.2 Development and Diversification

On the early railways the Boards would invariably appoint an engineer who would be responsible for all the engineering of the railway parts, both moving and fixed. Often the engineer would also be involved in the actual day-to-day operation of the railway. This had considerable advantage from a point of view of co-ordination.

As development of railways progressed, inevitably individual engineers became more specialised and there tended to be a loss of the overall or generalist view.


Fig. 1.1. Early railway construction.

It is the specific objective of the author of this textbook to encourage a wider view in railway engineering matters so that better appreciation of each other’s engineering requirements and constraints is achieved.

1.3 The Customer

In any consideration of the various engineering functions of a railway, the needs and aspirations of the customer must always be kept in the forefront of the mind. The passenger’s basic needs are to travel comfortably and to arrive safely at the destination reasonably on time. The freight customer needs confidence that his goods will be delivered safely and on time. Both want this service at a reasonable cost. All engineers and operators need to work together to achieve this objective. This seems so obvious and basic that it hardly needs stating. However ‘departmental’ and local interests can and often do arise which can jeopardise this simple objective and engineers and managers at all levels need to be on their guard.

1.4 The Operator

If the customer’s needs must be kept paramount then it follows that the operator’s requirements in satisfying the customer’s needs are also very important. Here however, there is room for manoeuvre. In satisfying the customer’s basic needs there is often more than one operational solution. In this case it is incumbent on both the operators and the engineers involved to jointly consider all the valid options which are available. A good example of this is the consideration of carrying out weekend essential works either over a number of shorter possessions of the railway or over one longer period.

The operator must also be able to deal with emergencies during periods of engineering work and contingency plans must be drawn up for this.

1.5 Overall Planning

In constructing and maintaining any railway system infrastructure, there always are many activities which are carried out in each of the engineering disciplines which overlap onto other disciplines/activities. This is inevitable. Proper co-ordination and co-operation is necessary here. There are also, from time to time, items of work where there is considerable overlap or ‘knock-on’ effect. A good example of this might be the requirement to renew a number of bridges on a certain line all of which carry signal cables or equipment which is nearing the end of life expectancy. Depending on relative costs in each area, an optimum programme could be drawn up jointly which would keep overall costs and disruption to a minimum in the long term. Similarly booking of long possessions to do work in one area might provide opportunities for other engineers to carry out other works at the same time, thus reducing expenditure overall. This type of co-operation is not always easy and does require a flexible attitude and acceptance sometimes of irksome restraints. However, maximum benefit of the whole must be the criterion.


Fig. 1.2. Underground railway construction at Blackfriars, London : 1871.

1.6 Choice of Route and Level

In the earliest stages of planning of any railway, choices have to be made relating to the best route, and which parts will need to be elevated or in tunnel. The route will be largely dictated by traffic demands and existing physical constraints, although in some instances, alternatives might be available where engineering and cost variations should be compared. In such cases, ground conditions and water levels as well as existing building foundations and services must all be taken into consideration. Again the level of the railway will be determined by existing physical constraints. It is essential however that all engineering implications are fully investigated and costed before any decision is made to construct a railway, either under ground or on elevated structure.

For underground construction full allowance must be made for the ‘full life’ costs of escalators, ventilation/air conditioning, lighting and other services, additional tunnelled accommodation for staff, fire protection and emergency exits etc. Disruption during the construction period of works in inner city areas is a factor that needs also to be taken into account when deciding whether or not to go underground.

Before adopting any form of elevated railway there needs to be a careful consideration of environmental issues including visual impact and noise as well as dealing with emergencies at high level. Although elevated railways occupy less ground level space than surface railways, the stations often cover more relative area because of the need for stairs, ramps and escalators etc.

From an engineering point of view also alignments should be as smooth as possible without steep gradients or tight curves to reduce wear on both the rolling stock and the track and to keep power consumption to a minimum.

1.7 Resources Required

For the satisfactory operation and maintenance of a railway, certain basic resources are required, which can be grouped into human resources, fixed assets and mobile machinery. Inadequacy in any of these three sides of this fixed triangle will mean that good operation cannot be maintained, irrespective of the performance on the other sides.


Fig. 1.3. Platforms and roof at Paddington, London.

Careful selection and adequate training of personnel at all levels is essential. Ongoing good relations with staff, both at national and local level, must have a high priority. This needs constant attention at all levels of engineering management. As in any large organisation, individuals need to feel that they are valued and that they have a positive part to play in the running of the whole enterprise.

The following chapters of this textbook deal with the outline requirements of fixed assets and mobile machinery that are necessary to satisfactorily operate and maintain a railway system. This relates to the various disciplines involved but it is vital to keep in mind that in all areas adequate human resources are often the key to success or failure.

The intention of this textbook is only to give a general engineering overview of all that is involved in designing, running and maintaining a railway. Because of this readers may need in certain areas, to look deeper. In an endeavour to point readers in the right direction, where this is the case, some details of extra reading have been provided at the end of some of the chapters.
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