  We have measured the rapidity distributions dN/dy of pi+/-, K+/- and p,pbar
in central Au+Au collisions at sqrt(s_nn) = 200 GeV. The average rapidity loss
per participant nucleon is 2.0 +/- 0.2 units of rapidity. The strange to
non--strange meson ratios K/pi are found to track variations of the
baryo--chemical potential in energy and rapidity.
