We discuss waves created in relatively thick plates by edge excitation at frequency-thickness (fd) products that
correspond, in principle, to multiple Lamb wave modes. For relatively low values of the fd product it is clear that Lamb
wave modes will be generated, while at large values of the fd product we observe a bulk (longitudinal wave) in the solid,
but influenced by reflections from the plate surfaces. We show that for a range of intermediate fd products a train of
regularly spaced nearly-longitudinal waves is generated. The development of a lead pulse and trailing pulses, all
traveling at the longitudinal (bulk) wave speed, is well known and has been explained in the literature. In this paper we
describe the transition from Lamb wave generation to the formation of nearly-longitudinal waves with their trailing
pulses. We report experimental results and theoretical results, with good correspondence between them. We also
examine the transfer of energy from leading to trailing pulses, which means that such nearly-longitudinal waves will not
propagate indefinitely; however, we show that they retain ample energy for flaw detection at distances of several meters.
Most importantly, we study the interaction of these trailing pulses with cracks, again showing experimental results and
theoretical predictions that are consistent with one another. The results suggest that these nearly-longitudinal waves are
an attractive option for flaw detection because of their shorter wavelength (as compared to Lamb waves at low fd
products) and because they preserve their pulse train characteristics after scattering.