  Longitudinal hadron spectra from Proton-Proton (pp) and nucleus-nucleus (AA)
collisions from $E_{lab}= 2$ AGeV to $\sqrt s=200$ AGeV are investigated. The
widths of the rapidity spectra for various particle species increases
monotonously with energy. The present calculation indicates no sign of a step
like behaviour as excepted from the Kaon transverse mass systematics. For
Pions, the transport simulation is consistent with a Landau type scaling of the
rapidity widths, both in central AA reactions and in pp collisions. However,
other hadron species do not follow the Landau scaling. The present model
predicts a decreasing rapidity width with particle mass for newly produced
particles, not supporting a Landau type flow interpretation.
