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10 years of rail welding

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So, it’s happy Birthday to the IoRW – the Institute of Rail Welding – which was formed ten years ago.

This auspicious event was marked by a technical seminar at the rather grand headquarters of The Welding Institute (TWI) on the outskirts of Cambridge. Granta Park at Great Abington was probably the best place to be on 28 June because the rest of Cambridge was effectively shut for graduation day and thus heaving with students and parents.

Ten years ago it was the vision of one man – Simon Hardy, then with Railtrack – who realised that track welding needed an organisational focus and needed to be aligned with the rest of the welding fraternity. Up until then it was in the shadows, fusing together large pieces of metal through a variety of unorthodox processes. Tim Jessop, Executive Officer, IoRW and Associate Director of TWI, started the day’s proceedings by leading the conference through the early days and by outlining the IoRW’s principle achievements which have been:

• Providing regular information to members regarding rail welding, including technical seminars, business briefings, a newsletter “Welding Lines”, and a website (www.iorw.org);

• Promoting the advancement of the technology of rail welding

• Promoting professionalism, competent control and best practice management of rail welding operations at all levels

• Encouraging training and qualification and continuing professional development at all levels.

The Innotrack project

Throughout the day, punctuated by a slap-up lunch, there were six further varied presentations with a wide coverage of rail welding and rail care. To start with, Jay Jaiswal of Tata Steel gave a briefing on the Innotrack project. Condensing 6½ years of research into less than half an hour was skilfully achieved. This was a personal view of research and its practical application tinged with, at times, pride at what has been achieved and frustration at what resides in the long grass.

The project started in 2006 and, although planned to end on 30 September 2009, was extended to December 2010. The supply industry invested €5.35 million, equivalent to about 386 man-months. This was a large sum, so there should be no problem questioning the benefits.

For the first time there was a systematic investigation of European track maintenance and renewal cost drivers. Priorities were identified for innovation to address the root causes of problem conditions, and innovation sub-projects successfully addressed these priorities.

A new tool for stiffness investigations was developed – the Portancemeter. As Jay remarked, “When you start to see new products then that’s a sign of successful research.” But then, when referring to the progress of an experimental slab track in Germany, he let slip the wry comment that when it comes to getting innovation adopted in the railway industry “It would be easier to get an appointment with Barack Obama”.

The Metro industry seems to be easier to penetrate as he noted in the second part of his presentation on the PM ‘n’ IDEA – an almost acronym for Predictive Maintenance employing Non-intrusive Inspection & Data Analysis. This is a more modest project of around five million Euros involving 16 partners comprising urban transport infrastructure managers, academic institutions, and supply industry members.

Solutions ready for use so far are:

• Non-intrusive inspection of track based on image analysis techniques;

• Assessment of internal integrity of grooved rails;

• Assessment of track quality with on board diagnostics;

• Scientifically validated methodology for establishing actionable wear limits;

• Vehicle mounted sensors & analysis techniques for track inspection;

• Track based sensors to impart intelligence into track components.

Whitemoor S&C repair facility

Out on the bleak, black Cambridgeshire Fens there is an establishment at Whitemoor occupied by rogues and villains. A place from which there is no escape. It’s Whitemoor HM Prison – rather than the Whitemoor National Track Materials Recycling Centre which is just down the road.

Network Rail’s Gary Munns and Richard Oliver are quick to emphasise that their facility is no scrap yard. Certainly, some material goes off to meet its maker, but there are concerted effects to reclaim most of the larger permanent way components using on-site expert welders. They have established a purpose built S&C repair facility at Whitemoor and are ever improving the equipment available. Their experienced welders use proven equipment, the ESAB BV1000 and the Matweld grinder, in an indoor environment so they have no possession limitations. They can also carry out “enhanced” 054 inspections because they have the necessary handling equipment to ensure that all parts of a component can be seen easily.

New cast crossings can have a long lead time – several weeks in fact. Gary and Richard have been able to supply a refurbished crossing within a few days. And with such material now being suitable for higher category lines, savings in train disruptions caused by failed components are considerable.

Mobile flash butt welding testing

Network Rail has made a commitment to mobile flash butt welding with the purchase of four machines mounted on 360° road rail excavators. The design and construction of the host RRV vehicle is a combination of a Doosan DX170W excavator with engineering carried out by GOS Engineering in Blaenavon, Wales.

The welding head is supplied by Holland Co. from Illinois, USA, and the generator is manufactured by Deutz and is rated at 450kVA.

John Hempshall of Network Rail outlined the testing procedure that these machines go through before they can work on the national network. Such is the prodigious output of these machines that it is vital their output is accurate and consistent.

The four machines that are currently being built will be used both for rail renewals and rail maintenance with a capability to ‘stress’ the rails in situ which will save valuable time and money. The machines have been going through the approval process over the last couple of months and should be in operation on the infrastructure later this year.

High Deposition Rate Surfacing

In a valiant and highly technical presentation, Tamas Sandor, of the Hungarian subsidiary of welding equipment specialists ESAB, gave a comprehensive outline of research into High Deposition Rate Surfacing (HDRS – a process used to repair the surface of the running table).

Conventional wisdom has been to use a high temperature pre-heat. This leads to issues with possession times and the high temperatures can lead to damage to rail bedding materials such as are used in tram tracks or with crane rails. But, of course, the high pre-heat allows a lower current to be used in the deposition of the welds metal. ESAB have experimented with a range of pre-heat temperatures with much higher deposition currents. The experiments were conducted with the three main rail repair techniques used today: MMA (manual metal arc), automated FCAW (flux-cored arc welding) with longitudinal weaving and automated FCAW with transverse weaving.

Results were tabled that showed that with automated methods, lower pre-heat temperatures could be used with little detriment to required hardness values.

Future aluminothermic welding moves

Richard Johnson, Thermit Welding (GB) Ltd, offered an overview from a supplier’s perspective of significant improvements to their processes over the last ten years. He also speculated about the outlook, particularly in the light of important changes occurring in the industry. There is no doubt that there will be fewer aluminothermic welds in the future.

Network Rail is putting an emphasis on mobile flash butt welding, and rail is being manufactured in longer lengths. But the aluminothermic welding process continues to provide a unique solution for joining of rails at site. It remains the only proven method for full fusion welding. It is applicable to all rail profiles, steel grades, and support construction. It is portable, cost effective and generally reliable and, above all, it has over 100 years’ service. Nevertheless, improvements can still be made, especially by focussing on reducing operator variability. Richard outlined developments in the GTSmartweld automated process currently on trial. Further improvements are in hand but these were referred to only as “version 2” in order to safeguard patent issues.

Tri-metal weld issues

Tri-metal welds are generally used at the leg ends of austenitic manganese cast crossings so that standard pearlitic grade leg end extensions can be fixed to the casting. These two materials cannot be successfully welded directly to one another and therefore a narrow stainless steel transition piece is flash butt welded into place between them. The extended pearlitic leg can then be welded into track with conventional aluminothermic or flash butt welding techniques, eliminating the need for a fishbolted joint.

Brian Whitney from Network Rail gave a presentation on the failure of tri-metallic welds, discussing the incidences and the numbers of failures in recent years along with the types of failure, their mode and pre-existing defects. He looked at the root causes and mechanisms of failure, the difficulties in managing them and the actions taken to reduce future occurrences.

Original failures occurred due to a manufacturing defect in the tri-metal weld. Initially, the affected welds were produced during cold weather but further failures have occurred with crossings produced all year round. More recently a second mode of failure has been observed where fatigue cracks have initiated from small casting defects within the stainless steel insert itself.

Another 10?

The IoRW has demonstrably fulfilled its original aim of creating a professional “home” for the rail welding community, and it has maintained its appeal through some very significant changes in the industry over the past 10 years. It is difficult to predict what the next 10 years might bring but the IoRW stands ready to meet the challenges that lie ahead. One thing is for sure – the industry will be continuing to rely on welding for many, many years to come!

Grahame Taylor
Grahame Taylorhttp://therailengineer.com

Structures, railway systems, railway construction, digital data

Grahame Taylor started his railway career as a sandwich course student with British Railways in October 1965, during which he had very wide experience of all aspects of railway civil engineering.

By privatisation, he was in charge of all structural and track maintenance for the Regional Railways’ business in the North West of England.

In 1996, he became an independent consultant, setting up his own company that specialised in the capturing of railway permanent way engineering knowledge using the then-new digital media. As a skilled computer programmer he has developed railway control systems and continues to exploit his detailed knowledge of all railway engineering and operations.

He started to write for Rail Engineer in 2006, and became editor two years later. During this time, he has written over 250 wide-ranging articles and editorials, all the while encouraging the magazine’s more readable style of engineering reporting.

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