Domestic and International Railway Manufacturers Combat Stress and Vibration with Innovative Fastener Thread Form

         Whether the challenge is getting a bearing adapter to reliably withstand tremendous force in a U.S. locomotive bogie frame, retrofitting Chinese track to handle a doubling of train speed, or cutting maintenance costs in Brazilian freight cars, Spiralock thread form is proving crucial in a variety of applications.
         "Some joints, especially below suspension level, must take the brute force of the track, and the direct impact of wheel on rail," says Steve Johnson, a Sr. Project Engineer at General Motor's Electro-Motive Division, the world's largest builder of commercial diesel-electric locomotives, based in LaGrange, IL. "Joints may be required to withstand 350,000 lbs. of traction, 1,000,000 lbs. of compression, and 1,250,000 lbs. of impact, for example, in railcar center plates or links," adds Paulo Mauricio da Rosa, Railway Engineering Manager for Amsted Maxion, a Cruzeiro, Brazil-based freight car manufacturer, who specified Spiralock on freight car bottom discharge doors and roof components, in addition to the initial application in freight car center plates.  "To prevent fastener loosening under vibration and improve safety and reliability, we intend to specify Spiralock in all railcar applications," explains da Rosa. "That will include airbrake components, support brackets, and other connections between nuts and bolts."
         Spiralock thread form not only holds the joint firmly together but also allows for both thermal expansion and contraction without slippage, an important consideration for extreme weather conditions. In China, for example, where rail track fasteners face temperature differences of up to 110° C due to exposed summer and winter weather, in addition to the stress and vibration of Chinese high speed trains, Spiralock has been adopted as a national standard. So far, 3,000 kilometers of track has been laid using the Spiralock fasteners and much more is on the way, including about 1,400 kilometers planned in a mountainous Tibet railway. To read more about railway applications in the U.S., Brazil and China, click here.