On the right track

When tracks are upgraded, maintained, or replaced, there should always be as little disruption as possible. This requires automated and reliable track-laying machines – such as those made by long-established Swiss company MATISA. The company swears by premium solutions from Fronius for their joining tasks.

On April 3, 2007, the French state rail company broke its own speed world record with a TGV: for the first time ever, a train, which was traveling on the Paris-Strasbourg line, reached the ultra-high speed of 574.8 kilometers per hour. In order to achieve this record run, the TGV needed to be specially tuned and this stretch of track remodeled. Work on the track included raising the level between the outer and innersides of the track on some bends to 13 cm. At speeds of almost 160 meters per second it, it is necessary to overcome high centrifugal forces and to safely avoid ballast pick-up on open sections of track. The experts therefore had to precisely measure the “train highway”, adjust the tracks to millimeter-precision, pack the ballast bed under the tracks, and remove each protruding stone with the upmost care.

EVERY MACHINE IS UNIQUE

High speeds aren’t the only reason for the growing demand in railroad track-laying and maintenance machines. Ever-decreasing time frames for pending works mean that measuring, construction, and maintenance machines have to manage a heavier workload with greater precision and maximum availability.

It’s for this reason that track construction machines from MATISA are in such high demand. The company, who began manufacturing construction and maintenance machines on the banks of Lake Geneva in 1945, have become a respected name in the industry thanks to the reliability of their machines. In some German-speaking countries, “matisern” (or “matising”) has even become a synonym for ballast bed tamping. Although MATISA pride themselves on the reliability of their machines, they believe that customer satisfaction is every bit as important. Customers from around the world can be sure that they will find a receptive ear when it comes to their special requests.

“This is because there are different track gauges and other regional variations, but also because we consider the supposedly smaller customer requirements. For example, installing a washroom could radically change the construction due to the closely packed design of the train and the altered weight distribution.” This is particularly true if the machine needs to be adapted to the customer’s specific workflows. For this reason, MATISA is rarely able to use standard components on any of its passenger or freight trains, meaning that the Swiss manufacturer produces all of the important parts it needs, including bogies.

COMPREHENSIVE AND DIVERSE WELDING OPERATIONS

MATISA has therefore kitted out its construction and production departments with the very best equipment. Out of a total 500 employees, 100 are engineers who look after the different levels of electrical and mechanical structures in the trains. Of the 400 staff in the production department, 50 are fitters and welders.

MATISA is EN 15085-certified and processes metal sheets and profiles made from conventional construction steel (S355) with thicknesses of between 10 and 200 millimeters to construct the trucks, bogies, and superstructures. The welding operations are diverse and comprehensive, accounting for around one-third of the time needed to build a tamper. Even for relatively simple products, such as transport wagons, hundreds of meters of weld seams are needed. After all, these wagons are 25 meters long, made out of metal plates with different widths, and are welded together from prefabricated five-by-five meter long box sections.

Each truck must comply with a geometrical dimensional record with extremely tight tolerances. The joining of the box sections with a 25 mm penetration depth is monitored through ultrasound and magnetic testing.

WITH FRONIUS POWER SOURCES – AND ALMOST EXCLUSIVELY MANUAL LABOR

Experts manually weld these and all other weld seams up to two meters long using conventional filler metal (1.2 m Böhler EMK 8 solid wire electrode). Welding is mostly carried out using the spray arc welding process (with plate thicknesses starting at 5 mm), but with longer longitudinal seams, the company uses a type FDV 22 MF battery-powered longitudinal chassis instead, which has a permanent magnet and optional oscillation. The MAG power sources used for manual welding at MATISA are also a Fronius solution.

The five parts of the trucks for the transport wagons are clamped on a positioning device in order to prevent out-of-position welding and to ensure the specified tolerances are met. Now the welders can start welding the box sections together. So that the frame does not buckle or become warped, specific welding sequences must be followed and the frame is turned around regularly to prevent deformation. Finally, the weld seams are subjected to both visual and non-destructive ultrasound and magnetic testing, as these are classified as a welded, safety-related component.

ROBUST AND RELIABLE DESIGN MAKES FOR MINIMAL EFFORT

Since MATISA introduced its first Fronius power source at the start of the 1990s, the machinery park has changed and become successively bigger over time. “It means that we can minimize our stocks of spare parts and consumables, allowing us to reduce our overheads.” Today the company’s welders have a total of 50 Fronius systems from several model generations at their disposal, such as the TPS 450, TPS 4000/5000, and eight TPS 400i. “Although we do not currently exploit the full capabilities of the latest generation of devices, we have approved various processes such as spray arc, dip transfer arc, and pulsed arc for our production process for metal plates from 5 mm thick. We are very happy with the equipment and the welding results,”explains Rony Chiavone. Furthermore, the use of a shielding gas mixture with only 8 percent CO₂ helps to avoid undesirable spatter and ensures a cleaner surface.

QUALITY AND PERFORMANCE IS VITAL

The company values the advantages that come with the state-of-the-art welding systems, such as touchscreen operation, sophisticated hosepacks, and the ergonomic, lightweight manual welding torches from the TPS/i family. “For MATISA, it is vital that there’s an innovative and highly capable premium manufacturer behind the devices, who operates a fastacting and competent after-sales network,” underlines Christophe Cochard. One member of this network is Plüss Sàrl, based only a few kilometers away from MATISA. Experts from the Certified Fronius Distributor have been supporting the mechanical engineering firm with equipment, consumables, expertise, and calibration services since 2017. “Powerful and reliable welding technology combined with an impeccable service helps us to fully utilize the tight production times,” summarizes Rony Chiavone. “With Fronius and Plüss by our side, we are well prepared for any current and future challenges.”