This book is intended for mechanicians engineering mathematicians and generally for
theoretically inclined mechanical engineers. It has its origin in my Master's Thesis (J 957)
which I wrote under the supervision of Professor Dr. R. Timman of the Delft TH and Dr. Ir. A.
D. de Pater of Netherlands Railways. I did not think that the surface of the problem had even
been scratched so I joined de Pater who had by then become Professor in the Engineering
Mechanics Lab. of the Delft TH to write my Ph. D. Thesis on it. This thesis (1967) was weil
received in railway circles which is due more to de Pater's untiring promotion than to its
merits. Still not satisfied I feit that I needed more mathe matics and I joined Professor
Timman's group as an Associate Professor. This led to the present work. Many thanks are due to
G. M. L. Gladwell who thoroughly polished style and contents of the manuscript. Thanks are
also due to my wife herself an engineering mathematician who read the manuscript through
critically and made many helpful comments to G. F. M. Braat who also read an criticised and
in addition drew the figures together with J. Schonewille to Ms. A. V. M. de Wit Ms. M. den
Boef and Ms. P. c. Wilting who typed the manuscript and to the Publishers who waited
patiently. Delft-Rotterdam 17 July 1990. J. J.
