Facility for Accelerated Service Te/tlng ‘ jL£ \ Hlgfi tonnage Loop TECHNICAL NOTE 1 FRA/ORD-91-16 WHEEL/TRUCK TOLERANCE EXPERIMENT AT FAST MAY 1991 \ FAST/HTL is an international, cooperative government-industry research program sponsored by the Federal Railroad Administration, the Association of American Railroads, and the Railway Progress Institute. This report has been prepared from test results produced by the AAR at the Transportation Test Center, Pueblo, Colorado, under contract to the FRA. The information that it contains is distributed by the FRA in the interest of information exchange. No portion of this report may be regarded as an endorsement by the AAR, TTC, the FRA, or the RPl. ’ 'l 03 - Rail Vehicles st Components j NOTICE This document reflects events relating to testing at the Facility for Accelerated Service Testing (FAST) at the Transportation Test Center, which may have resulted from conditions, procedures, or the test environment peculiar to that facility. This document is disseminated for the FAST Program under the sponsorship of the U. S. Department of Transportation, the Association of American Railroads, and the Railway Progress Institute in the interest of information exchange. The sponsors assume no liability for its contents or use thereof. The FAST Program does not endorse products or manufacturers. Trade or man­ ufacturers’ names appear herein solely because they are considered essential to the object of this report. 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. F R A /O R D - 91-16 4. Title and Subtitle 5. Report Date Wheel/Truck Tolerance Experiment at FAST May 1991 6. Performing Organization Code 7. Author(s) Association of American Railroads John Leary 8. Performing Organization Report No. 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Association of American Railroads 11. Contract or Grant No. Transportation Test Center P.O. Box 11130 Pueblo, CO 81001 12. Sponsoring Agency Name and Address 13. Type of Report or Period Covered U.S. Department of Transportation 1985 Federal Railroad Administration Washington, D.C. 20590 14. Sponsoring Agency Code 15. Supplementary Notes 16. Abstract The test program described in this report covers the investigation of the performance of trucks in freight cars influenced by various mechanical factors. The primary issue was the effect of axle misalignment on the behavior of three-piece trucks. Secondary tests were carried out to investigate the influence of wheel profile on wheel wear and truck design on wheel/rail forces. The testing was completed in four separate phases: (1) wheel wear testing, (2) instrumented wheel set testing to study wheel/rail forces, (3) single car and full train rolling resistance testing, and (4) steady state curving model predictions of wheel/rail forces. The intention was to derive basic relationships between the magnitude of axle misalignment and wear, wheel/rail forces, and rolling resistance. By developing a unified understanding of these factors, the implications regarding operating costs the railroads realize in terms of wheel and rail wear and fuel consumption can be appreciated. The culmination of this work represents a tabulation of results which may assist railroad operating personnel and railroad researchers in understanding some of the basic performance parameters which influence the performance of freight car trucks. 17. Key Words 18. Distribution Statement Wheel Wear, Axle Misalignment This document is available through Wheel Profile, Instrumented Wheel Sets, National Technical Information Service Wheel/Rail Forces, Truck Design, Rolling Springfield, VA 22161 Resistance, Rail Temperature, Steady State Cur­ ing Analysis 19. Security Classification (of the report) 20. Security Classification (of this page) 21. No. of Pages 22. Price Form DOT F 1700.7 (8-72) 1 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. F R A /O R D - 91-16 4. Title and Subtitle 5. Report Date Wheel/Truck Tolerance Experiment at FAST May 1991 6. Performing Organization Code 7. Author(s) Association of American Railroads John Leary 8. Performing Organization Report No. 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Association of American Railroads 11. Contract or Grant No. Transportation Test Center P.O.Box 11130 Pueblo, CO 81001 12. Sponsoring Agency Name and Address 13. Type of Report or Period Covered U.S. Department of Transportation 1985 Federal Railroad Administration Washington, D.C. 20590 14. Sponsoring Agency Code 15. Supplementary Notes 16. Abstract The test program described in this report covers the investigation of the performance of bucks in freight cars influence! by various mechanical factors. The primary issue was the effect of axle misalignment on the behavior of three-piece trucks. Secondary tests were carried out to investigate the influence of wheel profile on wheel wear and truck design on wheel/rail forces. The testing was completed in four separate phases: (1) wheel wear testing, (2) instrumented wheel set testing to study wheel/rail forces, (3) single car and full bain rolling resistance testing, and (4) steady state curving model predictions of wheel/rail forces. The intention was to derive basic relationships between the magnitude of axle misalignment and wear, wheel/rail forces, and rolling resistance. By developing a unified understanding of these factors, the implications regarding operating costs the railroads realize in terms of wheel and rail wear and fuel consumption can be appreciated. 1116 culmination of this work represents a tabulation of results which may assist railroad operating personnel and railroad researchers in understanding some of the basic performance parameters which influence the performance of freight car trucks. 17. Keywords 18. Distribution Statement Wheel Wear, Axle Misalignment This document is available through Wheel Profile, Instrumented Wheel Sets, National Technical Information Service Wheel/Rail Forces, Truck Design, Rolling Springfield, VA 22161 Resistance, Rail Temperature, Steady State Cur­ ing Analysis 19. Security Classification (of the report) 20. Security Classification (of this page) 21. No. of Pages 22. Price Form DOT F 1700.7 (8-72) I EXECUTIVE SUMMARY The Wheel/Truck Tolerance Experiment at FAST (Facility for Accelerated Service Testing) , Transportation Test Center, Pueblo, Colorado, investigated the effect of various mechanical factors on freight truck curving performance. This was accomplished through a series of tests that included (1) wheel wear tests, (2) measurement of wheel/rail forces, (3) rolling resistance testing, and (4) curving model analysis. This project was carried out to study a number of different parameters under known controlled test conditions. Past tests have been done that covered wheel wear, for example, but with no comparable measure of wheel/rail forces or rolling resistance for the same test vehicle(s) . The goal was to measure several aspects of truck behavior and thus provide more consistent understanding of wheel/rail interaction as affected by various mechanical factors. The wheel wear portion of the study demonstrated the role the wheel profile has on the initial wear rate at FAST. Under unlubricated running, the CN Heumann wheel profile reduced flange thickness wear by 27 percent in comparison to the standard AAR 1:20 profile during the "break-in" phase of operation. The GB cylindrical profile used by the Southern Pacific Railroad, in some applications, produced only a marginal reduction in flange wear when compared to the 1:20 profile. After the profiles had worn in, there was very little difference in wear rate, and the ultimate running surface geometries were nearly identical. The effect of axle misalignment on wheel wear was signif­ icant. Working within the available tolerances of typical three-piece trucks, wheel wear was increased by more than an order of magnitude when held in extreme levels of radial misalignment on FAST. ii Similarly, the rolling resistance of trucks with various degrees of fixed misalignment increased considerably with the level of radial misalignment. In general the resistance was proportional to the wheel wear measurements. Wheel/rail forces were measured for standard three-piece trucks and a retrofit steering truck on curves up to 7.5 degrees. Both lateral and longitudinal forces were radically reduced by the steering truck under loaded, semiloaded, and fully loaded conditions. In most cases the reductions were on the order of 60 percent to 80 percent depending on track curvature. Forces between the wheel and rail under various states of radial axle misalignment were measured on curves up to 12 degrees. The misalignment of axles affected the lead axle L/V (lateral over vertical) ratio most significantly at curves up to 7.5 degrees. In the 10.5- and 12-degree curves there was little difference. Trains of increasing weight were tested for tractive effort requirements on the FAST loop. These results were then compared to calculations using the modified Davis equation. The pre­ dictions were low for the longer trains. The wind conditions were not factored into the calculations but were documented at the time of the test to be in the 5 mph to 15 mph range. This may have contributed to the apparent discrepancy between measured and calculated resistance. During the train resistance test, rail-head temperature rise was measured and was found to be a rough indicator of energy dissipation depending on train weight and track curvature.