having a concave inside surface 42 for supporting the lateral edges of the traveling screen 12 the 34 inside 34 orientation refers to the rail side most proximate of the screen 12 and the stock pond 16 the top of rail 40 is crowned with a plurality of flushing fountain sections 43 each about 18 to 24 inches long as illustrated by fig3 each fountain section comprises a square section fluid conduit 44 and a side plate 45 the fluid conduit provides a flat top surface 46 penetrated by holes 47 and 48 between the upwardly projected inside surface of side plate 45 and the weir edge 49 of top surface 46 similar to the holes 36 and 3 in the deckle structure flushing fountain holes 47 and 48 have an alternating bore axis oritentation with the axis of holes 47 aligned at substantially 0 u00b0 with vertical and the axis of holes 48 set at an angle of 15 u00b0 to 45 u00b0 from vertical toward the top surface weir edge 49 the lower projected surface of side plate 45 provides a mounting clamp and alignment fence whereby the fountain section 43 may be secured to the rail element 41 to obtain minute adjustments of the screen 12 travel profile the edge cupping rail 41 is often secured to the paper machine forming table in.