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PERMANENT WAY & INFRASTRUCTURE


Gauge corner restoration


Brian Zielinski-Smith, marketing executive at Welding Alloys Ltd, discusses the increase in track wear on light rail systems and what can be done about it.


E


mbedded track wear and cracking has proved to be a


big player in the stoppage and derailment of trams. There has been an increase in tramway traffic volume, which has been growing in terms of passenger numbers year- on-year and is set to continue, so keeping these transport veins in operation is becoming more and more vital. This increase in traffic, along with the type of trams being used today, has added to an increase in wear on grooved rail, especially on gauge corners.


This wear profile typically forms a lip due to the flange of the wheel being forced down the gauge face, as a loss in height on the rail head as occurred; this is noticeable at


around 1mm. Over time this wear continues past 5mm, causing significant loss in height of the rail and the thinning of the lip to the point where it folds over, trapping grease, debris and moisture, which, left unchecked, damages the rail and introduces additional factors into tram rail degradation.


In standard usage, a curve requires repairing every three to five years, and is instigated once the appearance of a minimum of a 3mm wear profile is noticed.


If the rail is not repaired in this time, the check rail can start to wear and increases the chance of permanent rail damage or tram carriage derailment, both of which


far exceed by many times the cost of wear control.


Recognising that uncontrolled wear is a major problem to tramways around the globe, Welding Alloys has made major investments in developing new materials and technologies to handle the welding processes required to successfully control and repair the wear seen on embedded track.


Those companies managing tramway lines traditionally undertake a manual repair operation, but with an ever increasing volume of passengers and frequency of routes, Welding Alloys has noticed this type of wear is happening quicker than can currently be manually maintained.


The current MMA (Manual Metal Arc) track maintenance operation can be very time-consuming and is heavily reliant on the competence of the individual welder and in some cases can lead to the formation of internal defects within the rail surface as it becomes prone to porosity.


Welding Alloys specialises in automated submerged arc welding technology using continuous wire processes which, as a direct replacement for MMA, offer far improved technical and economic benefits, primarily as a result of faster deposition rates, higher weld quality and greater heat input.


To add additional weight to this process change, Welding Alloys has designed and developed an automated SAW Gauge Corner Restoration (GCR) welding machine, specifically developed for welding embedded track.


The company has been able to 52 | rail technology magazine Aug/Sep 13


differentiate itself by providing tramway maintenance companies with the ability to monitor the weld deposit in real time and provide full data-logging functionality.


Because of this it is now possible to provide a full and comprehen- sive ‘quality trail’ for every sec- tion of track repaired; in addition this allows the systems’ controls and parameters to be completely customised & programmed, mini- mising repair time and increasing welding deposit control by giving precise feedback and position in- formation.


This system, which is fully integrated into their automated GCR welding machine, focuses on meeting the stringent quality requirements of tramways and rails within the transport industry.


Thorough testing and assessment has played a vital and key role in the advancement of tramway maintenance through extensive R&D being carried out by Welding Alloys on its control systems, machines and welding wires.


Welding Alloys can report that through metallurgical and field tests, the tramways, using their specialised welding equipment, showed that the repaired track (which work hardens) significantly outlasts those rails which are either not repaired or use traditional MMA processes. Welding Alloys reports that its control system and GCR machine significantly increases the accuracy of weld deposits minimising weld defects and rework found in more traditional MMA operations, proving to be an additional USP for their product range.


FOR MORE INFORMATION


T: 01763207500 W: www.welding-alloys.com


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