Light Rail for better public transport
Making LRT systems safe — Part One, Article from the October 1998 edition of Tramways & Urban Transit
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Light Rail Transit Association
Light Rail for better public transport |
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Making LRT systems safe — Part One, Article from the October 1998 edition of Tramways & Urban Transit
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Major Christopher 'Kit' Holden has been the public image of safety for promoters, builders and operators of 'new generation' light rail for many years. Now retired from the Railway Inspectorate, and a busy consultant, he explains how the modern safety regime has evolved.
At the outset I must make it plain that this article represents my own views which are not necessarily the views of Her Majesty's Railway Inspectorate or any other Government or statutory body.
It would, however, be foolish to pretend that, after some 19 years in HMRI, my views have not been shaped by or helped to shape those of the Inspectorate. With that Government health warning out of the way I can begin to set the scene on the safety regime, principles and standards for the LRT industry in the UK today and perhaps compare it with what can be found elsewhere.
In this first article, I plan to concentrate on the foundations and the general framework of safety policy and then look in more detail at the infrastructure, including signalling, at vehicles and operations, and finally a look at the way ahead coupled with a little wishful thinking. I have also adopted the current practice of referring to ‘trams’ rather than the earlier term LRV; the latter was coined to indicate that the vehicle was one that ran on an LRT system but was not confined to steel wheel on steel rail technology and to avoid, in the public’s mind, any connection with the type of tramway which had all but disappeared from the streets of Britain.
The current safety policy for the construction and operation of all forms of LRT systems in the UK is contained in the documents Railway Safety Principles and Guidance Part 1 and Part 2 (Section G), which for convenience can be referred to as RSPG 1 & RSPG 2(G) respectively. Obviously these did not spring out of thin air but had their origins not only in early tramway legislation but also that for railways. It was as the result of the latter that not only was the Inspectorate formed but also the underlying precepts which guided its conduct and very much influences today’s thinking. For example, it established from the outset the principle that railway companies were responsible for the safe operation of their systems and also the principle of approval of the construction of a railway before it was opened for traffic in the hope, not always fulfilled, that thereby accidents would be avoided. At the time, the early 1840s, Victorian politics considered that Government interference in private enterprise should be kept to the minimum. Thus, once a railway had reached the standard necessary for its opening to be approved following inspection, the railway company was expected to maintain it to that standard without further inspection. A third principle, that the Government could not be held responsible for the safe design of structures built by the railways, followed later as a result of the collapse of the Tay Bridge in 1879.
When the Greater Manchester PTE was planning the legislation which would enable them to construct Manchester Metrolink there were only, effectively, two documents which governed tramways in Great Britain; The Tramways Act 1870 and the so-called 1926 Memorandum. Neither of these seemed entirely appropriate to what was being planned so the Inspectorate paid a number of visits to systems in Continental Europe to see for themselves what arrangements modern light rapid transit systems had.
Before I became directly involved, Hanover, perhaps the closest in concept to the Manchester scheme, had been visited but little had been done to update the legislation or to consider what the impact might be on matters which normally fell outside the Inspectorate’s responsibilities. Perhaps I should add, on a personal note, that having lived in Germany for a number of years I was well acquainted both as a user and as a driver of other road vehicles of how to cope with trams.
The traditional mechanism for developing and publishing updates to existing standards for railway construction and operation was to issue a revision to the Department of Transport’s Railway Construction and Operation Requirements; commonly called ‘The Requirements’ or the ‘Blue Book’. This document had been in existence since its first publication in 1858 in ever-expanding form. Despite the title it mainly covered construction matters, including signalling, but very little about pure railway operating matters. It had never covered rolling stock and it had never dealt with tramways. Perhaps it was thought that the only tramway matters worthy of stipulation were already adequately covered in the 1870 Act; later deficiencies in the Act being covered by the 1926 Memorandum.
To a certain extent the precedents for introducing new ‘subjects’ into the Requirements had been set by the issue of the revised safety clearances which stemmed from the introduction of overhead electrification on the main line railways and latterly by the issue of the Level Crossing Requirements which had drawn together the individual requirements for the different types of modern level crossing protection which were replacing the old-fashioned, traditional, gates. Hence what was envisaged was either a short section or even a stand-alone part of the Requirements to bring the 1926 Memorandum up to date for a tramway running in the road traffic conditions of the 1990s. The work on the Level Crossing Requirements had been multi-disciplinary and involved highway and road traffic engineering and signing as well as the Railway Inspectorate and British Railways. The seeds of what was to come had already been sown.
The later, special, or enabling acts for London Underground Railways and that for the Tyne and Wear Metro had stipulated that, in addition to matters already within the ambit of Section 41 of the Road & Rail Traffic Act 1933, rolling stock for those railways also required approval before being taken into use. This was therefore also incorporated into the acts for the Manchester scheme. Because vehicles of the general type which were likely to be used in Manchester already existed in Germany and had much in common with those in Newcastle and on the Docklands Light Railway, the need to produce detailed requirements was not particularly urgent. Besides, such details theoretically only needed bilateral agreement between GMPTE and HMRI.
This was, however, not true of the highway engineering aspects of the Manchester scheme. Whilst the requirement to prescribe such matters as road traffic signing and the control of road junctions was well understood in the Inspectorate, the need for urgency was, with a few notable exceptions amongst the tram enthusiasts, much less well recognised in the other relevant divisions in the Department of Transport many of which felt that, even after the 1988 No.2 Act had received Royal Assent, Metrolink would never happen. Nevertheless a working party was assembled, the nucleus of which was based on those who had been involved with the level crossing exercise, and the result of their labours was later published in April 1989 as the Provisional Guidance Note on the Highway and Vehicle Engineering Aspects of Street Running Light Rapid Transit Systems (PGN for short). Work on the revision to the Requirements had, perforce, to take second place to the PGN. As it happened even the PGN was not ready by the time the tender documents for the Manchester scheme were issued but it was sufficiently well advanced for well-founded advice to be given, via the PTE, to potential contractors.
What were the precepts which guided the authors of the PGN? In general it was felt that the basis for the subject matter should stem from the provisions of the 1870 Act and the 1926 Memorandum but without necessarily following the numbers which would need re-assessment in the light of current road traffic conditions; wide departures from these would have made it difficult for existing systems, principally Blackpool.
Equally the experiences gained from the visits to continental systems should be used for guidance on the issues rather than for slavish copying because road traffic conditions and the general attitude to road traffic law were very different to those in the UK. Besides it was guidance which was being prepared and adherence to one particular ordinance or another would have been totally inappropriate.
There already existed a body of legislation and precedent, in the shape of the Blue Book, on electrification systems. There seemed no point in trying to vary these nor to depart from the 1926 Memorandum in the matter of wire heights over streets, despite an early view in the first edition of the PGN that those used for main line railways at level crossings would be adequate. Electrical clearances were expected to follow the Blue Book rules. Some time later it was realised that these were perhaps excessive and were much larger than those required by IEC 913 and this has been recognised in RSPG 2(G). Similarly physical clearances followed the principles in the Blue Book but it was felt that, in the interests of mobility impaired passengers, the rules for the platform edges would have to change. The integration of platforms into the street-scape would need careful attention.
The guiding principle for street-running was that the path swept by the tram was to be obvious to all road users and especially to those pedestrians who were blind or partially-sighted. Equally, other obvious traps for the unwary had to be avoided, for example moving point ends should be well away from places where there were likely to be large congregation of pedestrians and consideration given to the particular dangers faced by motor- and pedal- cyclists. Whilst it was accepted that systems such as Manchester might need railway-style signalling this was not appropriate for purely street-running systems. Much time during the continental visits was taken up by study of the various road junction signalling and control methods, including the signing and traffic signals themselves. These were far from standardised, even within individual countries. It was also recognised that, if trams in the UK were to be exempt from the observance of the red (stop) road traffic signal, a totally different form of signal would be required to differentiate it from not only traffic signals for other road users but also from railway signals, whose green aspect conveyed an altogether different meaning. The LRT signal used in the UK represents what was felt to be the best amalgam of continental practice. Similarly a different range of road traffic signs was needed which had to be observed by tram drivers but not by others. Trams were not to conform to existing construction and use or lighting regulations for other road vehicles, but the lighting regime was to make it obvious that the vehicle was a tram and safety features designed to prevent injury to pedestrians or damage to other vehicles in an accident were to be incorporated.
The PGN only gave a bare outline of the body of advice which was being developed in the light of having to make decisions as to what would be acceptable in both Manchester and Sheffield. Instead of it being a highway engineer’s addendum to the Requirements, the PGN became the basis for the actual Requirements themselves. These had been completely drafted as part of the revision of the whole of the Requirements but were never issued in that form because of the decision to recast the entire format of the latter in the shape of the new Railway Safety Principles and Guidance. Later articles will examine how the early precepts for LRT systems developed into RSPG 2(G) and whether, in the light of experience, they are still valid.
Making LRT systems safe Pt. 1: top of page