U.S. Patent 8,876,014 (November 4, 2014), "Polyurethane Ballast Layer, The Method for Preparing the Same and the Use thereof," Chenxl Zhang, Gang Sun, Yi Shen, and Hui Zhao (Bayer Material-Science AG, Germany).
A railroad track bed consists of a ballast layer of crushed rock set on the road base supporting rails and ties. This ballast distributes the heavy train load onto the road base, reduces road base distortion, and enables smooth and safe travel with Impact reduction and shock absorption. However, ballast maintenance is essential--and costly, involving large equipment.
Zhang et al. developed a polyurethane spray for ballast consisting of polyisocyanates with alkyl groups, polyether polyols or amines, and a blowing agent. The porous coating reduces ballast crashing, shifting, and cracking under heavy loads. This prevents dirt, snow, and wastes from entering into the Interstitial spaces of the ballast, thus extending the track bed's maintenance cycle--reducing costs as well as improving safety.
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|Title Annotation:||INDUSTRY PATENTS; patent received|
|Article Type:||Brief article|
|Date:||Feb 1, 2015|
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