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TOP OF RAIL FRICTION CONTROL |
Quantifying the Benefits of Top of Rail Friction Control
By Richard Reiff • July, 2006
Top-of-Rail friction control has been shown to significantly reduce lateral loadings and stresses on the track structure. Lingering application and economic issues, however, have hindered widespread implementation of top-of-rail (TOR) friction management systems by North American freight railroads.
In order to address this issue, the Transportation Technology Center, Inc., in conjunction with its 11th Annual Technical Review, brought together a group of railroad users, researchers and suppliers to discuss what has worked, what hasn't, and the issues preventing TOR technology from finding more widespread acceptance and use. While the emphasis was on experience with wayside applications, discussions included mobile-based application issues.
Railroaders discussed their experiences with TOR friction control applications in revenue service. One Western railway reported, for example, 25% to 30% reductions in curving forces at five locations where wayside TOR friction control is being evaluated. It found that the benefits are reduced, however, in areas with bi-directional traffic. Nonetheless, the railway expects the use of TOR friction modifiers to allow it to reduce curving forces in 6-degree curves to those in typical 3-degree curves. An Eastern road reported that it achieves curving force reductions by applying TOR material to the low rail only, but cautioned that operator oversight must be maintained.
Another Western road is evaluating the effectiveness of 12 TOR units on an eight-mile segment with 2% grades and heavy curvature, including several back-to-back, 8-degree reverse curves. The railway is expanding its trial by adding 15 more applicators with plans to monitor curving forces, rail wear and fuel consumption. It also will monitor rail surface conditions and defect development with and without TOR materials. It has determined, thus far, that rail surface defect performance is site specific, depending on train speed, elevation and curvature.
While wayside equipment is generally performing well, with most of the application problems associated with the prototype systems ironed out, railroaders want to be able to measure TOR systems' effectiveness. Is the delivery system working? Is the product being applied effectively to the rail and wheel? Is the TOR system delivering the optimal coefficient of friction?
