Rail                  package:nlme                  R Documentation

Evaluation of Stress in Railway Rails

Description:

     The 'Rail' data frame has 18 rows and 2 columns.

Format:

     This data frame contains the following columns:

     Rail an ordered factor identifying the rail on which the
          measurement was made.

     travel a numeric vector giving the travel time for ultrasonic
          head-waves in the rail (nanoseconds).  The value given is the
          original travel time minus 36,100 nanoseconds.

Details:

     Devore (2000, Example 10.10, p. 427) cites data from an article in
     _Materials Evaluation_ on ``a study of travel time for a certain
     type of wave that results from longitudinal stress of rails used
     for railroad track.''

Source:

     Pinheiro, J. C. and Bates, D. M. (2000), _Mixed-Effects Models in
     S and S-PLUS_, Springer, New York.  (Appendix A.26)

     Devore, J. L. (2000), _Probability and Statistics for Engineering
     and the Sciences (5th ed)_, Duxbury, Boston, MA.

