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February 2010



Maintenance Of Way Article
Thermite welding equipment and techniques



Maintenance Of Way

By Walter Weart

Although thermite welding began in the United States in the 1930s, it dates back to 1893 and was patented in 1895 by German chemist Hans Goldschmidt.

The aluminothermic welding reaction sometimes is called the "Goldschmidt reaction."

"Our company traces its origin back to Dr. Goldschmidt," says David Randolph, president and chief executive officer of Orgo-Thermit Inc., adding that the equipment and service supplier has been involved in thermite welding for more than 100 years.

Suppliers have continued to refine thermite welding equipment and techniques for decades. But more recently, they've delved heavily into research and development to keep coming up with other processes, products and services that offer a more effective rail weld at a lower cost.

Orgo-Thermit's R&D efforts have led to the Full Head Repair Weld, a process designed to remove transverse defects in the head of the rail. The weld removes a rail defect, but leaves the rest of the rail intact, and takes about 30 minutes to install compared with two hours to install a rail plug with two thermite welds, says Randolph. In addition, the Full Head Repair Weld can cut costs by several thousands of dollars, he says.

In April 2008, Orgo-Thermit began to test the weld at Transportation Technology Center Inc. (TTCI) in Pueblo, Colo. The company is seeking ways to further improve the weld and process, says Randolph.

"Another area we are researching is the installation of Head Repair Welds on defective plant welds or electric flash-butt welds," he says.

In addition, Orgo-Thermit has developed 1.5-inch gap welds via research conducted with the University of Illinois in 2004. The welds are "less susceptible to common defects normally encountered in a one-inch gap weld when using large rail profiles," says Randolph, adding that the welds were installed in track on a heavy-haul Mexican railroad and so far have shown "great success."

Coming To a Head

Railtech Boutet Inc. has completed some R&D of its own and now is offering a Head Wash Repair (HWR) system that can be used to repair transverse and corner gauge defects.

"This repair can be completed in 40 minutes vs. installing a rail plug and two welds," says Railtech Boutet Executive Vice President and Chief Operating Officer Oliver Dolder, adding that the company is testing the system to repair defective plant welds and flash-butt welds.

Rail first needs to be ground up to one inch in depth and up to two inches in width before the HWR system is used to make a repair. The simplicity of the system and a shorter installation time "provide the user an additional easy and inexpensive option to make track repairs," says Dolder.

After a successful first round of tests at TTCI, the company received a final report from the Colorado center and will begin marketing the Head Wash Repair Weld in spring, he says.

The company has demonstrated the Head Wash Repair Weld to BNSF Railway Co., CN, Canadian Pacific and Union Pacific Railroad, says Dolder.

Railtech Boutet also offers aluminothermic welding systems, and a range of rail welding kits for worn rail and wide-gap welding. The company is in the final stages of launching production of its CJ One-Shot Crucible at a Napoleon, Ohio, plant.

Later this year, Railtech Boutet plans to conduct more tests as part of its continuing study on high-carbon and high-strength rail. The company is designing a weld kit for those rails.

"This will be closer to the metallurgical properties of those types of special rails, which will accommodate those railroads that are currently using these types of rails in mainline track and/or tangents and curves," says Dolder.

KLK-USA Co. continues to test a welding product, too. By March's end, the company expects to obtain bending and "metallographic" test results from TTCI on "high-strength lane" specimens of ELPA, a single-shoot weld that's installed at the base of rail, KLK-USA officials said in an email. In addition, Norfolk Southern Railway plans to perform its own similar tests, they said.

The ELPA weld's temperature is significantly lower than that of exothermic welds, the officials said. The ELPA weld is available in a breakable mold and offers a kit including everything needed to complete the weld, according to KLK-USA.

TTCI already has completed other tests on the weld with "positive results" showing the ELPA does not affect the internal structure of the rail because the temperature doesn't surpass 500 degrees Celsius, KLK-USA officials said.

In addition to seeking more product sales in the United States, the company is striving to boost business in Mexico. KLK-USA already has a presence there because Ferrosur S.A. de C.V. has more than 4,500 of its welds in track, according to the supplier. The company also has made presentations to Mexico's subway operator that met with "very good acceptance," KLK-USA officials said.

Currently, the company offers six product lines: line resistance, grounding, contact wire, soldering iron, soldering copper and "cableducto," the officials said.

In addition to North America, KLK-USA markets its welding products in Europe and South America.

Meanwhile, Holland Co. L.P.'s welding division — which offers flash-butt welding services via mobile trucks, fixed plants and off-track ATVs — continues to develop welds designed to consume less rail.

Holland's Low Consumption Weld has "greatly improved productivity" since less rail consumption equates to less labor and continuous-welded rail adjustments, says Kevin Flaherty, vice president of maintenance-of-way sales and marketing. Holland introduced the product about seven years ago and obtained American Railway Engineering and Maintenance-of-Way Association (AREMA) weld approval last year.

Since the company introduced the Puller Lite in the 1990s, electric flash-butt closure welds are "quicker, easier and more economical to install," he says.

The Low Consumption Weld and Puller Lite (160-Ton Puller) were developed based on customer demands, says Flaherty. One area where the Low Consumption Weld Holland has made strides is reducing labor, he says. A crew might typically have to work on 500 or 600 feet of track, but with the weld, they might need to work on only 300 feet of track, says Flaherty.

"The crew does not have to remove nearly as many rail anchors in connection with the Low Consumption Weld as they would with a regular weld," he says.

Holland also continues to refine the Intelliweld control program developed in 2002. The program enables the company's fleet of welders to react more quickly to rail movement and other parameters that affect weld quality.

"We continually work on improving our weld quality and consistency," says Flaherty.

On the Move

RibbonWeld L.L.C., which has offered in-plant welding since 2002, is trying to up the product-improvement and quality ante by offering additional mobile welding services.

"We started with our Springfield, Mo., plant and now have three field crews with complete mobile welding facilities on hi-rail trucks to handle our customers' requirements," says RibbonWeld President Gary Bevills.

The company also operates its own rail train and will pick up rail and either weld it onsite or take it to a plant. RibbonWeld's welding machines offer a number of features, such as a computer program that ensures the machine produces the same welds each time and records information to a hard drive to eliminate paper records, says Bevills.

In addition, mobile units are equipped to provide remote monitoring and repair, and feature an onboard camera to observe work.

A Lasting Impression

Last year, RibbonWeld introduced a five-point welder head system to control all aspects of a rail's alignment during the weld, says Bevills, adding that the weld meets AREMA specifications.

"We see continuing demands from the railroads to have the welds last as long as the rail," he says. "This is an area we are working on."

There's an emerging area of the rail industry that Geismar-Modern Track Machinery (MTM) is focusing on. The supplier is working to ensure the company can provide welding equipment that meets high-speed rail needs.

"We supply a wide range of components with experience in supplying equipment to meet high-speed rail tolerances, which should be beneficial to our market when high-speed becomes a reality," says MTM General Sales Manager Alan Reynolds.

MTM also offers equipment for in-plant welding and support equipment for thermite welding. In addition, the company provides an array of weld shears, including those for girder rail, profile grinders, rail pullers and rail saws for thermit welding, says Reynolds.

Two years ago, MTM developed a model MP-23 profile grinder for in-track welders that enables the operator to stand. TTCI is using the machine.

"The grinder consists of a frame that supports the grinder and engine, eliminating the weight during the grinding process and allowing the operators to grind more welds without fatigue that previously occurred," says Reynolds. "Our customers are seeking enhancements that will make this type of work safer and reduce the weight of the equipment."

Space Saver

Railroads are demanding improvements to welding equipment used on manganese frogs and manganese crossing diamonds, too. Lincoln Electric Co. has tried to answer that call by providing the Air Vantage¨ 500. Developed more than five years ago, the machine combines an air compressor and welder to save space, "which is critical in fitting the equipment to the vehicle," says Brian Meade, Lincoln Electric's manager of railroad technical services-global accounts.

Used by CSX Transportation, the Air Vantage 500 allows for arc gouging with defect removal up to three-eighths of an inch. The machine can use wire welding that's faster and requires less heat to be applied to the casting, says Meade. The Air Vantage 500 also can supply power for electric grinders and air-operated equipment.

"An across-the-arc wire feeder gets power to operate its motor from the arc voltage of the power source, [which] eliminates the need for a separate control cable to supply power to the motor," says Eric Snyder, Lincoln Electric's senior product manager of engine-driven welders.

For the past three years, the company also has offered the LNª-25 PRO, a portable industrial wire feeder. Among the machine's features: split wire guides that provide full support for wire throughout the drive path and eliminate "birdnest" tangles, says Meade.

Weighty Issue

Stanley Hydraulic Tools also offers equipment designed to weld manganese castings. The company markets the RW20, a robotic, computer-controlled arc-welder used to repair rails and frogs. BNSF is the welder's first user, says Stanley Director of Marketing Kelly Steck.

"We started several years ago to develop equipment that would eliminate the potential for workers to inhale manganese-laden smoke," he says.

The company also aimed to "take the welder out of a worker's hands" because older equipment is very heavy, says Steck. After two years of R&D, Stanley developed a unit that weighs 42 pounds and enables a worker to stand, he says.

The RW20 can record all welding events, and features automated pattern and dimension controls to provide consistent welds.

Like all welding equipment suppliers and service providers, Stanley continues to seek ways to enhance its machines to make the welding process easier, better and cheaper.

"We are looking at automating the wire feed adjustment and the grinding process for the RW20," says Steck.

Walter Weart is a Denver-based free-lance writer.



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