QUICK AND COST-EFFECTIVE REPAIRS TO WORN TRAM RAILS

Tram operating companies and maintenance contractors are under pressure to cut costs, without compromising on quality or service. When it comes to repairing worn rails, there is a simple way to achieve this goal. ESAB's specialist Tramtrac™ II equipment, used in conjunction with a suitable welding power source and self-shielding wires, can reduce the investment required and simplify repairs to worn inside and outside running edges of embedded rails, as well as railheads.

The Tramtrac™ II is a small, lightweight (12kg) welding tractor and wire feed unit that is designed specifically for repairing embedded tram rails. Unlike SAW processes that might need substantial equipment installed in a 20-foot shipping container or similar, the Tramtrac™ II, welding power source and 20kVA generator set can be readily carried in a pick-up truck. Furthermore, the tractor unit is easy and quick to mount on the rail and remove again, which makes it feasible to repair rails while trams are still running, without having to take possession of the track. As well as an integral wire feed unit, the Tramtrac™ II incorporates controls for travel speed, wire feed speed, inching and start/stop of the welding process.

ESAB recommends the Origo™ Mig 410 for use with the Tramtrac II. This is a heavy-duty, step-switched power source that delivers 400A/34V at a 50 per cent duty cycle and is well suited to the needs of welding 1.2 and 1.6mm flux-cored welding wires. It can be used with cables up to 35m long and the unit benefits from a rugged galvanised casing and special software to ensure high reliability in applications such as tram rail repairs. An optional digital meter provides an easy-to-read and accurate display of the welding parameters that remains visible even after welding has finished.

There are two self-shielded, austenitic welding wires that ESAB offers for tram rail welding applications, namely OK Tubrodur 14.71 and OK Tubrodur 15.65. Both of these FCAW wires achieve excellent material properties on high-carbon R260 (UIC 900A) grade rails with no need for preheating. This means that operators need not wear breathing apparatus for protection from the fumes generated when rubber anti-noise/vibration mountings are subjected to heat. Furthermore, the self-shielding nature of the welding wires eliminates the need to use shielding gases, which saves money and simplifies logistics. Both OK Tubrodur 14.71 and OK Tubrodur 15.65 generate minimal slag, thereby helping to minimise the time on site and the costs associated with waste disposal.

Tramtrac™ II units are already being used successfully to repair rails in Riga (Latvia), Gothenburg (Sweden) and elsewhere. Users find the equipment quick and simple to use, and repairs typically need only minimal post-weld grinding.