NA57 at the CERN SPS has studied the production of strange particles in Pb–Pb and p–Be collisions. Hyperon enhancements at 40 A GeV/c are presented and compared to results at 160 GeV/c beam momenta. The momentum spectra are analysed based on hydrodynamical models and freeze-out temperature, transverse and longitudinal flow velocities are extracted. Central-to-peripheral nuclear modification factors at 160 A GeV/c are calculated.