Interface - The Journal of Wheel/Rail Interaction

RAIL GRINDING

Practical Rail Grinding (continued)

One problem is that traffic on the network has increased significantly since the profiles were designed and by 2007 is expected to be double what it was in 2001. This will make the original rail profiles obsolete unless the grinder can maintain the grinding interval established in 2001. The tonnage increase is in the form of more trains which reduces the track time available for grinding and creates difficulty in sticking to the desired grinding interval.

Another problem is that two of the designed rail profiles have proven difficult to implement due to their high metal-removal requirements, especially when grinding them into rails with a large crown radius. The intent of the two designs (one is a tangent profile, the other is for low rails) was to shift the contact towards the field side, particularly for the low rail profile. This would add a small positive increment to the maximum rolling radius difference in sharp curves and help ensure that contact was spread across as much of the wheel tread as possible. Interim steps have been initiated to meet the original profile objectives while reducing metal-removal requirements—a further attempt to emphasize practical achievability over installing the "perfect" profile. (See "Preventive-Gradual On-Cycle Grinding: A First for Brazil," published in the proceedings of the 8th International Heavy Haul Association conference in June 2005.)

Despite the benefits proven in the past, rail maintenance managers struggle to justify, retain and manage rail grinding programs with limited budgets. Still, tests have shown that rail grinding can effectively extend the life of rail in track. As reported by P. Sroba and M. Roney in "Rail Grinding Best Practices" at the 2003 American Railway Engineering and Maintenance of Way Association's annual conference, one North American Class 1 railroad compared no grinding, corrective grinding and preventive grinding strategies in test zones. Table 1 shows a significant increase in rail life with preventive grinding because rail was replaced due to wear instead of fatigue. This railroad continues to use test zones for refining its wheel/rail maintenance strategies by monitoring the interaction between different grinding strategies, gauge-face lubrication and top-of-rail friction management. The railroad recognizes that grinding and friction management are crucial to a healthy wheel/rail interface and adjusts both strategies to optimize the results.

Railroads embarking on a grinding program may not be able to adopt a preventive grinding strategy immediately. Often, the railroad will be struggling with a particular problem, such as corrugation, hunting, or broken rails from rolling contact fatigue. Once the immediate needs are addressed, however, a practical and achievable preventive grinding program that optimizes wheel/rail interaction will best serve the railway property's best interest.

Fred Prahl, is Director - Sales and Marketing; Eric Magel is Senior Engineer; Peter Sroba is Principal Engineer, National Research Council Canada, Centre for Surface Transportation Technology.

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