The difficulties and expenses involved in field experiments on wheel-r
ail system wear forced researchers to use, whenever possible, laborato
ry tests. The major problem in laboratory tests is how to transfer the
results obtained to the real wheel-rail system. Modeling of the wear
process between wheel flange and side face of a rail head is studied a
nd discussed. It is noted that the laboratory tests with rolling-later
al sliding better simulates wheel flange and rail head wear. Four wear
modes, referred to as mild, severe, heavy and catastrophic, have been
identified in the laboratory tests. The heavy wear mode has not been
identified before. The catastrophic wear mode has been observed at the
lateral creepage of 5%. The wear modes that occur in worn wheel flang
es and in side-worn rails have been found to correlate with those foun
d on the rollers during laboratory tests. The boundaries of wear modes
in terms of product of maximum contact pressure and creep value were
defined. The hypothesis of wear mechanisms responsible for wear proces
ses was suggested. (C) 1998 Elsevier Science S.A.