i--;
      }
    }
  }

  /* Find the pChild pointer for each node. 
  **
  ** The pChild points to the node directly above on the same rail.
  ** The pChild must be in the same branch.  Leaf nodes have a NULL
  ** pChild.
  **
  ** In the case of a fork, choose the pChild that results in the
  ** longest rail.
  */
  for(pRow=p->pFirst; pRow; pRow=pRow->pNext){

        pRow->railInUse = 1<<pRow->iRail;
        continue;
      }
      pRow->iRail = findFreeRail(p, 0, pParent->idx, inUse, pParent->iRail);
      pParent->aiRaiser[pRow->iRail] = pRow->idx;
    }
    mask = 1<<pRow->iRail;
/*    if( pRow->pPrev ) pRow->pPrev->railInUse |= mask; */
    if( pRow->pNext ) pRow->pNext->railInUse |= mask;
    if( pRow->pChild==0 ){
      inUse &= ~mask;
    }else{
      inUse |= mask;
      assignChildrenToRail(pRow);
    }