\HeaderA{Rail}{Evaluation of Stress in Railway Rails}{Rail}
\keyword{datasets}{Rail}
\begin{Description}\relax
The \code{Rail} data frame has 18 rows and 2 columns.
\end{Description}
\begin{Format}\relax
This data frame contains the following columns:
\describe{
\item[Rail] an ordered factor identifying the rail on which the
measurement was made.

\item[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.

}
\end{Format}
\begin{Details}\relax
Devore (2000, Example 10.10, p. 427) cites data from an article in
\emph{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.''
\end{Details}
\begin{Source}\relax
Pinheiro, J. C. and Bates, D. M. (2000), \emph{Mixed-Effects Models in S
and S-PLUS}, Springer, New York.  (Appendix A.26)

Devore, J. L. (2000), \emph{Probability and Statistics for
Engineering and the Sciences (5th ed)}, Duxbury, Boston, MA.
\end{Source}

