David Wardale's Article from Steam Railway Magazine

A NEW STEAM LOCOMOTIVE DESIGN FOR MAIN LINE SERVICE

This is the unabridged text of the first of two articles about the 5AT project, written by David Wardale. A slightly abridged version appears in Steam Railway magazine's June 21st 2002 edition No. 272. The articles are reproduced with the kind permission of Steam Railway Magazine.

David Wardale's renown Class 26 4-8-4 No. 3450, the Red Devil, was an attempt to address the disadvantages of steam traction.  But - despite its success - the South African 4-8-4 suffered from being a rebuild as opposed to a completely new design. The strikingNo 3450 pilots one of its ancestors' - 25NC No. 3410 - near Kilmarnock,South Africa on June 14th 1999PART 1: GENERAL CONSIDERATIONS

Some four years ago I wrote an article entitled Whither Steam Now? (Steam Railway, April 1998) questioning the future of main line heritage steam and suggesting the form a new steam locomotive for charter service might take. Four years on we still have heritage traction hauling main line specials, so it might be thought my predictions of hard times ahead were unfounded. However the difficulties of operating such locomotives on a modern railway are always increasing. Consider that:

  1. Normal scheduled passenger and freight services, which charter trains must fit in with, are becoming ever more frequent and faster. To obtain satisfactory timetable paths for charter services on densely trafficked main lines will therefore become increasingly difficult using motive power which cannot keep up with the speeds of other trains and which requires inconvenient halts for supplies.
  2. The consequences of locomotive failure become more serious on an ever more crowded railway.
  3. The safety requirements for train operation are becoming ever more rigorous, a trend which is driven by the changing conditions of railway operation, i.e. denser traffic and higher speeds.

Reflecting these trends (which will accelerate if the investment programme now planned for Britain's railways is implemented) Railtrack's conditions for allowing steam traction to operate over its network have already changed. Gone are 'grandfather rights' which accepted that locomotives were safe to run because they had done so in the past. Instead every locomotive operating on Railtrack controlled infrastructure is now assessed by engineering and safety standards that are hard, and in certain respects impossible, for heritage traction to meet. Heritage locomotives do not therefore satisfy current requirements and are allowed to operate only because Railtrack accepts their non-conformance with its standards. But this comes at a price - heritage traction is limited to 75 mph and 15 000 miles per annum, restrictions which are imposed to make the risk, which operating such locomotives poses to other users of the railway network, acceptably low.

Main line steam charters will ultimately have to run faster to slot in with other services, otherwise arranging suitable paths for them will become impossible, but higher speeds will only be allowed if steam complies more closely with modern safety requirements and demonstrates an ability to operate reliably at continuous high speed - both of which will be difficult to achieve with locomotives over 40 years old (or new ones built to designs of that era).

Railtrack has anticipated these problems. Its Railway Group Standard GM/RT2000, 'Engineering Acceptance of Rail Vehicles' states:

"Where there is growing risk from continued operation of non-conforming vehicles, including heritage and special service trains, the Directorate shall normally give five years' advance notice of intention to withdraw all certification and to prohibit any future re-certification."

This should make alarm bells ring concerning the future of main line steam. It is obvious that the risk to the punctual and safe operation of the railway from heritage locomotives will grow as these locomotives become older and speeds and traffic density rise. Railtrack (or its eventual successor) will demand higher safety and reliability from heritage steam, and the cost of delivering this, even if technically feasible, will forever escalate. It also brings home that steam is only allowed to operate by the grace of Railtrack A change of personnel or thinking at Railtrack, a serious incident involving steam, or simply a feeling that the risk it poses on main lines has become too great to accept, any of these could result in a steam ban. At worst this could be a blanket withdrawal of the right of heritage steam to run on all main lines, although a more likely initial scenario is that steam will get banned route by route as routes are upgraded and their services become more frequent and / or faster. Such routes are likely to be those serving main population centres, where most of the charter train business probably originates, the secondary routes to which steam may be increasingly confined being not necessarily where charters can be most profitably operated.

The railway is now very different from that on which steam used to run in regular service, a difference which is constantly increasing as the railway adapts itself to a changing world. The time will therefore inevitably come when the limitations of heritage locomotives will force them off main line rails. If steam is to survive on the main line it will need to fit in more seamlessly with a modern railway, and this has prompted the present writer and some of his associates to explore the possibility of producing a new locomotive of the type suggested in my 1998 article. The aim of this proposal is to have a steam locomotive working charter trains at speeds which are compatible with those run by modern traction, and which could be intensively utilised to give an adequate return on its appreciable capital cost. The new locomotive would therefore have to be accepted for operation on Railtrack lines without the limits imposed on heritage steam.

The proposed locomotive has been designated the Class 5AT, the '5' in recognition of it being based on the size and format of the BR Class 5MT 4-6-0, and the 'AT' standing for Advanced Technology. The drafting of a business plan for the proposal has given some insight into the difficulties that such a scheme would face, and has resulted in interesting feedback and suggestions from various people in the railway industry.

Firstly, Railtrack's five years' notice of intention to withdraw all certification from heritage steam would be insufficient time to develop a new locomotive - eight years would seem to be about the minimum time required to get a new design in service if starting from scratch. Railtrack has advised that the proposal would have to undergo the same full engineering acceptance procedure as any other new locomotive design, which is much more rigorous than that applied to heritage traction. It follows that if it were to be accepted on this basis it would not be classed as a heritage vehicle and would not be subject to any future ban that may be imposed on heritage steam, thereby realising one of the project's main aims. However to avoid the possibility of a truly steamless railway, onto which it might be very difficult to reintroduce even non-heritage steam, it would appear wise not to wait for any ban to be announced before starting work on such a project. Rather, an advanced steam locomotive should already be running and its performance proven whilst Railtrack's existing policy still applies.

The question of the technical acceptability of the proposal to the railway industry is heavily linked to safety considerations. Acceptance of any vehicle for operation on Railtrack controlled infrastructure involves an assessment of the operational risk by various authorities, e.g. Railtrack itself, Railway Safety and H. M. Railway Inspectorate. Railtrack's engineering acceptance procedure is designed to ensure that new rolling stock is safe to run in its intended service and is generally compatible with the rest of the railway, and involves compliance with specifications given in the company's Railway Group Standards. There are 34 such standards, plus 14 additional codes, which appear to be relevant to any new design of steam locomotive. They cover features ranging from such simple items as the yellow warning panel at the ends of locomotives (not required on heritage steam), to not so simple ones, such as modes of structural collapse and energy absorption under collision conditions. Certain features of the proposed locomotive would be dictated by the necessity of satisfying these Railway Group Standards to the maximum possible extent. In general, it is expected that the Class 5AT would relate to these standards in three ways:

  1. Areas where full compliance could be demonstrated at the design stage. This could be achieved for all details which are not constrained by the very nature of steam traction.
  2. Areas where full compliance could be designed into the locomotive, but where proof of this would require testing, such as braking performance, track forces and ride quality.
  3. Areas where steam traction's fundamental nature may prevent full compliance from being achieved, such as the impossibility of directly obtaining a completely unobstructed view ahead from the cab front windows.

All three areas involve potential difficulties. For example, the design of any new vehicle must be certified compliant by a Conformance Certification Body (CCB), but in this case there would be many areas where there is no precedent which a CCB could use for guidance regarding the proposal's acceptability - how many steam locomotives have been built with (intentional) energy-absorbing zones? The same problem would apply to components not covered by the Railway Group Standards but which have a bearing on safety and reliability, such as the engine's reciprocating parts, the design of which would have to be in advance of anything yet seen in steam locomotive engineering. Approval of the design would therefore be likely to prove difficult and expensive.

However, it is the last of the above three areas, i.e. the basic trade-off between the need to retain the steam locomotive's classical form and aesthetic appeal and the consequent non-compliance with certain Railway Group Standards, which would be the key issue in the question of the proposal's acceptability for safe operation. Specific derogation for each item of non-compliance with the mandatory requirements of the Railway Group Standards would have to be sought by making a sound case that such non-compliance did not compromise safety. Risk assessment would then be carried out by the authorities concerned to determine if the operating risk was as low as reasonably practical, in which case certificates of derogation might be granted. This risk assessment would naturally be linked to the operating speed and annual utilisation of the locomotive - the greater these were, the more rigorous the safety case would have to be. This being so, it is unlikely that clearance would be given for high-speed operation or more intensive utilisation without convincing practical demonstration of high-speed safety and reliability. The probable best scenario would be for initial acceptance to run on Railtrack lines to be granted with similar restrictions to those imposed on heritage traction, and for these restrictions to be progressively relaxed as the Class 5AT demonstrated its reliability and suitability for safe operation at higher speeds.

The basic aims of the present proposal have already been put to Railtrack for its consideration and advice. From its reply it is clear that the first step in the engineering acceptance process for the Class 5AT (and indeed for any new design of steam locomotive) would be a rigorous point-by-point review of the locomotive's compliance with the Railway Group Standards, listing specific areas of non-compliance and the degree of non-compliance in each case. This safety case would then have to be presented to Railway Safety for its views on possible ways forward for the project in relation to engineering acceptance. As permission to operate the locomotive at its full potential would depend on the ultimate outcome of this process, this work would appear to be the correct starting point for the whole project, and as such it could be undertaken as a feasibility study into the very possibility of high-speed and relatively frequent main line steam locomotive operation.

Railtrack has also advised that the fitting of automatic train protection (ATP) systems to rail routes, and the equipping of the locomotive with such a system, which may be technically possible, would be likely to significantly mitigate a number of risks due to non-compliance.

The acceptability of the locomotive to the operator (such as EWS Ltd.) and its staff should present no great difficulties, as steam crews should be attracted to the exhilarating performance which the new locomotive would offer. The functions of the driver and fireman would be basically the same as on any steam locomotive, although improved controls and the elimination of the manual labour of firing, either through oil firing or mechanical coal firing, would make their tasks easier. Nevertheless the art of driving and firing a steam locomotive, the practising of which is one of the main attractions for volunteer crews, would still be very much an ingredient of successful operation. Crews would naturally have to be passed for working at the locomotive's maximum continuous operating speed, 112.5 mph (180 km/h) being the target figure.

'Pacifics' such as 'Duchesses', rebuilt 'Bullieds' and unique BR '8P' No. 71000 Duke of Gloucester are generally considered to be the ultimate British locomotives.  But even such 'modern' designs are hopelessly outmoded, warns David Wardale.  The 'Duke' shows off its powerful front end at Ramsbottom on Feb 25th 1985The other main aspect of the proposal's acceptability to the railway industry is its commercial attractiveness to the locomotive's owner and its users (charter train operators). The business plan predicts good profitability for the Class 5AT over its anticipated operational life of thirty years, either on the basis that it is hired out to charter operators in the same manner as heritage steam, or used together with dedicated stock as a unique tour train. However in order to generate a profit the locomotive would have to be fairly intensively utilised - profitability calculations have been made on the assumption that it would be utilised at an annual rate equivalent to three 200-mile trips per week. Whether or not there would be sufficient demand for this to be realised might ultimately depend on the reaction to the locomotive of the railway enthusiast community and the general public. The latter is already taking over as the main customer for charter trains, and does not have the same attachment to steam traction as the enthusiast. One of the main charter operators has advised that for its average customer what is at the head of a train is not so important any more, which reduces both the commercial value of steam traction and the premium which can be charged for steam haulage. This, together with the presumed lower cost of using diesel or electric traction in charter service (this assumes the Class 5AT would be operated on a fully commercial basis without its costs being distorted by the factors applicable to heritage steam, such as volunteer labour), would diminish the commercial attractiveness of the proposal to charter operators.

The question of whether even steam enthusiasts are sufficiently interested to justify the proposal must also be raised. What is not wanted - or not shown to be wanted - will not materialise. There are many who see the rightful function of steam operations as preserving or recreating the past, and for them any proposal for a new design of locomotive lacks the essential element of historical preservation. Whilst we can promote the Class 5AT as a new and exciting shape on the rails, the preservationist would rather see old shapes restored or replicated. Both points of view are valid, but the latter ignores the writing on the wall for main line heritage operations. At some point - no one knows exactly when - it will surely be a case of new steam or no steam at all.

Turn to Part 2 of David Wardale's Article or close window.


Note: David Wardale's book describing his work and his achievements is titled "The Red Devil and Other Tales from the Age of Steam". Copies of the second edition of this book can be procured from:

Close Window