The Institute of Rail Welding (IoRW) was founded 15 years ago by Railtrack as one of the more positive outcomes that followed from the shocking Hatfield train crash in the year 2000. The idea for the IoRW is attributed to Simon Hardy, then one of Railtrack’s track engineers and now working for the ORR. The Institute has been a great success, and has contributed significantly to the massive reduction in the number of weld failures and broken rails that has been achieved on the rail network.
The Institute was the result of a collaboration between Railtrack and The Welding Institute (TWI), without whose expertise in welding the venture would not have succeeded. Fortunately, the IoRW initiative was taken forward by Railtrack’s successor, Network Rail.
The affiliation of the IoRW with TWI also has the benefit that it is able to offer its members professional registration with the Engineering Council at the appropriate level – EngTech, IEng or CEng.
The celebratory conference was held in York, in association with Network Rail and the National Railway Museum. The morning consisted of a number of demonstrations related to rails and rail welding, and took place at Network Rail’s new complex in the Engineer’s Triangle.
French supplier CTF and Network Rail jointly demonstrated CTF’s Translamatic 152 wire feed arc welding repair system. This is capable of carrying out automated repairs to worn rails and S&C components, taking as little as one hour to repair a typical crossing. This includes the crossing nose and both wing rails, and leaves the crossing ready for finish grinding before being returned to traffic. The whole welding cycle is controlled by the software in the control unit – the operator selects the appropriate cycle for the task in hand before leaving it to complete the weld automatically.
CTF offers a full package of equipment to power and support the welding unit, including a caterpillar-tracked transporter with a built-in three-phase generator which feeds the inverter that supplies the welding current.
Thermit GB was another demonstrator that has an interest in the use of higher voltage power on site. Its Smart Weld aluminothermic welding system, incorporating Smart Weld Jet, Smart Weld Record and Smart Weld Ace, uses atmospheric air instead of oxygen to burn the propane fuel to pre-heat the rail ends for welding. Like the CTF system, this one is controlled by computer software, ensuring that the flame is perfect and that correct timings and temperatures are adhered to. All the weld pre-heat parameters can be entered into the Smart Weld app using Bluetooth to connect the pre-heater to a mobile device for this purpose.
The actual weld is made using Thermit’s already well-known systems, so those details are entered via bar codes on the materials used. The associated water mist weld cooling system ensures faster, controlled cooling of the weld after shearing, and will save around 15 minutes on the time taken to complete a weld. This could be very valuable under restricted track access conditions such as are increasingly common on the UK’s rail networks.
Railtech, another French company, was also showing off its latest products in Network Rail’s new workshop, specifically designed and built for welding training. Its HWR rail defect repair system uses aluminothermic weld technology to repair a rail after a defect has been removed by cutting out a semi-circular piece of the head. Railtech also offers computer control of the process, this time via its ‘gas box’ control box, which governs the pre-heating process.
The Railtech team also demonstrated completion of a weld, including the Startwel ignition system and new hybrid felted weld moulds. The latter make it quicker, easier and more reliable to seal the moulds to the rails, and can be easily modified to compensate for rail wear.
German rail equipment manufacturer Robel showed its 13.49 modular rail grinder together with the associated power pack, model 70.02. The grinder is for weld finishing and similar rail profiling operations, whether associated with rail joining or rail weld repair. The grinding head depth is precisely controlled and the head pivots about the rail on a fixed frame, enabling accurate control of rail profile achieved.
The power unit is a hybrid device which stores energy from the idling grindstone and releases it during grinding. This allows the power pack to have a smaller motor-generator unit. Although the combined weight of grinder and power pack is greater than a conventional integrated unit, but each unit separately is light enough to be safely lifted by just two people. The power pack also has the potential to drive other Robel machinery such as weld shears.
Trueflame was also present, displaying a wide range of equipment for welding, gas cutting and related purposes including specialist PPE for welders, BV1000 accessories and wire feed systems.
British Steel showed its Zinoco corrosion-resistant rail, and demonstrated how this coating can be removed where welding is required, and then replaced afterwards.
There was a small demonstration from TWI of a rail and weld ultrasonic inspection system which deploys a 64-element head generating a divergent beam. The system for analysing the returned signals allows inspection of a much larger volume of the rail than previously possible, and so can obtain equivalent results to a conventional ultrasonic flaw detection system whilst scanning at 30mm intervals, compared with the normal 1mm interval. As conventional ultrasonic rail flaw detection trains can travel only up to 40mph, this might be a major benefit.
Network Rail’s John Hempshall showed Rail Engineer the ESAB wire feed welding equipment similar to the units specified for the company’s new maintenance trains. These will be the ESAB Warrior welding set and the 301ABS wire feed unit – a neat device that is fitted into a briefcase-sized ABS case.
After lunch, the day continued with presentations by several speakers. The first was David Godley, head of engineering capability at Network Rail. He has only recently taken on this new role, working for chief engineer Jon Shaw. He gave his keynote address on the theme “Innovation & Inspiration”.
David referred back to 17 October 2000, the day of the Hatfield derailment, and spoke of the great changes that have followed. Rails have changed, with CEN60 replacing CEN56 for most main line applications, and aluminothermic welding has also improved significantly – thanks to the IoRW, suppliers and others.
As a keen cyclist, David used the analogy of a bicycle wheel, strong and light as long as it is not abused by, for example, excessive stresses caused by potholes. Rails are the same, and cannot be expected to survive if abused by poor track conditions or significant wheel flats.
David also explained a little of his new role, managing engineering capability across all the engineering disciplines in Network Rail. He and his team are putting into place an “authority to work” process, based upon individual competence, and taking this back from the human resources function into engineering where it belongs. There will be a single competence framework for all professional engineers and asset managers in the company.
He described the need to focus upon safety, compliance and performance, and the imperative to maintain a balance between these three, rather than letting any one of them dominate at the cost of the others. He also covered business-critical rules, and the conflict between eliminating human error from systems to make them safer and the risk that, if this is taken too far, humans become too reliant upon the system protecting them. If that occurs, then disaster may follow through failure to spot a system weakness or flaw, or through human error over-riding the system in some way.
Looking at derailment numbers per annum by failure type, S&C failure is still the greatest risk. Following the latest improvements in welding and rail defect detection and rectification, rail break statistics are now dominated by breaks caused by foot damage and flaws.
David spoke of other initiatives, such as the skills assessment scheme and the six ways to maintain competence, the plain line pattern recognition project and the introduction of under-sleeper pads.
He concluded with some of his ideas about the future of society and of rail.
Reflections on the past
Brian Whitney, chair of the IoRW management committee, followed, presenting some of his reflections on the past 15 years. Brian has to take a great deal of credit for his own contribution to the IoRW and the successes Network Rail has had in significantly improving its rails and rail welds performance in this period. He was far too modest to say this, of course, but it is worth saying here.
Brian described, as we have heard before, the dramatic fall in rail break numbers since 1998/9, from 952 in 1998/9 to the latest figure of only 94 in 2016/7, the lowest ever result.
He referred to the Bushey derailment (abvoe) on16 February 1980, caused by a failed weld, which went undetected until the sleepers under it collapsed badly enough to derail an express train. Fortunately, despite some serious injuries, no one died. He looked at the report of the formal inquiry and the causes identified by this. These ranged from technical items like the incorrect positioning of the moulds when the weld was made, to organisational and administrative matters such as the lack of adequate resources and insufficient supervisory attention.
The need for a greater sense of craft pride and skill was mentioned, very relevant to David’s fear of making things too dependent upon some inhuman system and making people feel they are no longer responsible or in control. Records, skills and training, standards and auditing were all mentioned as issues. These matters are all just as relevant today, despite all the improvements that have been made.
Brian moved on to consider the record of rail welding. Like the rail break record, this is excellent, with the trend from 504 failed welds in 1979 to only 13 in 2016. This despite the vastly increased percentage of the network that now has welded rails (CWR). Furthermore, the 2016 figure also includes welds in S&C whilst the earlier statistic is for plain line alone.
The proportion of rail breaks occurring in aluminothermic welds was around 25 per cent for many years, but in the last four or five years this has begun to fall, now standing at 15 per cent. This is better than elsewhere in Europe. Brian considers this is due to better equipment and techniques introduced in the UK in recent years.
With rail defects dropping significantly, other issues are being shown up. Weld alignment problems are assuming greater significance, for example. Dipped welds lead to dynamic forces which cause ballast attrition and, potentially, failures of rail and/or sleepers. Misalignment laterally or rotationally causes wheel/rail contact forces that lead to rolling contact fatigue damage to the rails.
Defects or damage in the rail foot are becoming the most significant rail failure initiators, now that the other ones have been largely eliminated. Since these are hard to detect by the currently available technologies, it is difficult, at present, to remove them before they cause a rail break. Failures of arc-weld rail repairs are similarly hard to detect until they lead to rail failure.
Brian emphasised the importance of using available tools to identify in advance where there may be a problem and deal with it before a failure occurs. Thus, the use of LADS (Linear Asset Decision Support) and track geometry data may point out, say, a dip in the rail where there is no joint. Aerial inspection can be used to examine a site to help identify why a track fault exists or why track geometry is deteriorating abnormally fast. The challenge, as ever, is making management information out of the huge quantities of data available.
Brian concluded by reading out a message from one of the other people who helped to establish the IoRW so successfully – Tim Jessop, retired former Associate Director of TWI and founding Executive Officer of the IoRW. Tim spoke of those who helped start the Institution, Simon Hardy in particular, and of those who came a little later, Brian Whitney, Bill Mosley and Bob Sawdon. He expressed his pleasure at the progress that has been made and sent his best wishes for the future.
Solving MFBW design flaws
Next to speak was Bob Hervey, project manager for mobile flash-butt welding (MFBW) at Network Rail. He spoke of the history of the technique in the UK, going back as far as the Sersa machine of 1986. From there, he briefly outlined his history with the technology, including his past vow never to go near it again!
Despite that, he ended up taking on his current role a little while ago, and has since been trying to understand the problems associated with Network Rail’s MFBW machines, to correct these and to get the machines working as productively and effectively as they should.
When Bob arrived in his role, the machines that had been purchased were giving problems. Acceptable welds were rejected by the computer welding management system, welds were being left incomplete, and there were occurrences of loss of signal and system failure.
Designated K945, the machines were specially built for Network Rail. They were far more complex than other machines from the same stable, used extensively without problems elsewhere, chiefly because of a demand that they should be able to stress as well as weld.
Bob described the steps taken to confirm what it was about this complex design that was leading to the difficulties experienced before his arrival. Eventually, it became clear that it was the system incorporated in the K945s to allow the head to open by 400mm as compared with the 150mm opening of the normal K920 head used elsewhere.
Bob described the steps that are being taken to modify the machines to eliminate this problem and make them perform. The seventh unit has been modified through a proper engineering change management process and full welding approval testing has been done. It will now be used to relaunch MFBW within Network Rail.
A Golden Age
“The Golden Age of Rail” was the title chosen by Daniel Pyke, product marketing manager of British Steel – the company renamed by Greybull Capital when it bought the long products division of Tata Steel UK in 2016. British Steel now produces about 600 kilotonnes of rail per annum in around 100 different rail profiles, and can roll rail lengths in excess of 100 metres.
Daniel considered whether we are now in the Golden Age of Rail, examining what was meant by a golden age, looking at statistics on rail passenger travel, freight tonnages and network growth around the world. The UK, he said, is doing far more with little new network assets, whilst delivering the sort of improvements in such things as rail break statistics that earlier speakers had outlined.
The rail-related challenges that the railway faces include rail wear, plastic flow, rolling contact fatigue (RCF) and corrosion. British Steel has solutions to assist in managing these issues. HP335 rail steel is designed to reduce wear and RCF, and reduce grinding requirements, plastic flow and corrugations, while Zinoco rail coating prevents corrosion and increases durability, and is itself resistant to damage.
Although Daniel considered that this may be the Golden Age, he stated that it is imperative the railway continues to improve in order to maintain competitiveness in the future, implying that tomorrow will be even better than now!
It fell to Chris Eady, associate director of TWI and interim executive officer of the IoRW, to round off the day.
While other speakers had looked back at the first 15 years of the IoRW, Chris looked to the next 15 years, speaking first of the proposed IoRW Strategic Action Plan 2017-25. This has four themes:
- Support for Rail Infrastructure Controller decision-making;
- Development/implementation of Rail Welding best practice;
- Delivery of Rail Welding personal competence;
- General education/awareness of rail welding.
He spoke of the challenge of success – if rail welding becomes so well managed that rail welds cease to be a problem, how does the railway ensure that funding, resources and attention continue to be given to it to make sure that it continues to be problem free?
Chris continued by looking in more detail at the strategic themes and how IoRW might take them forward in order to meet this challenge effectively. In his opinion, immediate action needs to be taken concerning application standards, research priorities and strengthening relationships with rail industry bodies like RDG, RSG, RIS, NSAR and PWI.
All of which will ensure that the Institute of Rail Welding will be around for at least the next 15 years.
This article was written by Chris Parker.
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