Modeling Tamping Recovery of Track Geometry Using the Copula-Based Approach

Assessing and maintaining track geometry within acceptable limits are key components of railroad infrastructure maintenance operations. Track geometry conditions have a significant influence on rider comfort and safety. To maintain the ride quality and safety of the track, maintenance activities pertaining to track geometry, such as tamping, are performed. Tamping enhances the track geometry quality but fails to return the track geometry to an as-good-as-new condition. Majority of studies have evaluated tamping recovery using deterministic techniques, which assume that tamping recovery is dependent on the track geometry quality prior to tamping. However, they fail to capture the uncertainty of the recovery values. Probabilistic approaches are increasingly being used to account for the uncertainty but fail to model the underlying dependence between the variables, which may exhibit nonlinear dependencies such as tail or asymmetric dependence. To accurately model the tamping recovery phenomenon, this research conducted by University of Delaware employs the copula models in combining arbitrary marginal distributions to form a joint multivariate distribution with the underlying dependence. Copula models are used to estimate the tamping recovery of track geometry parameters such as surface (longitudinal level), alignment, cross level, gage, and warp. The results of this study showed that the after tamping recovery (correction) of the track does not behave like a traditional two-parameter normal distribution but rather has a distinct distribution (a three-parameter log-normal distribution) which can be used to better predict the results of the track tamping operations. Similarly, non-normal, behavior was also observed for the track quality condition before and after tamping.


    • English


    • Status: Completed
    • Funding: $75000
    • Contract Numbers:


    • Sponsor Organizations:

      Office of the Assistant Secretary for Research and Technology

      University Transportation Centers Program
      Department of Transportation
      Washington, DC  United States  20590
    • Managing Organizations:

      University of Delaware, Newark

      College of Engineering
      Newark, DE  United States  19711
    • Performing Organizations:

      University of Delaware, Newark

      College of Engineering
      Newark, DE  United States  19711
    • Principal Investigators:

      Attoh-Okine, Nii

    • Start Date: 20170101
    • Expected Completion Date: 20210831
    • Actual Completion Date: 0
    • USDOT Program: University Transportation Centers Program

    Subject/Index Terms

    Filing Info

    • Accession Number: 01701888
    • Record Type: Research project
    • Source Agency: University Transportation Center on Improving Rail Transportation Infrastructure Sustainability and Durability
    • Contract Numbers: 69A3551747132
    • Files: UTC, RIP
    • Created Date: Apr 17 2019 1:07AM