anchor.diff:            DTT=DT/XSI
             DT=DTT
             GOTO 100
  +        ENDIF
  +CMWF WHAT HAPPENS IF STEP THROUGH ELEMENT BUT XSI NOT > 1?
  +        IF(ISTEPOUTSIDE.EQ.1)THEN
  +           DTT=DT/2.000D0
  +           DT=DTT
  +           IF(IDEBUG.GT.0)THEN
  +              WRITE(6,*)'WARNING ELTRAK12 ISTEPOUTSIDE= ',ISTEPOUTSIDE,
  +     &             ' XSI= ',XSI, ' RESTEP DT= ',DT
  +           ENDIF
  +           GOTO 100
           ENDIF
   C
   C B. WHEN THE ENDING LOCATION IS EITHER WITHIN THE ELEMENT OR 
  
positive.code: C        
        ELSEIF(RATIO.LE.1.0E0)THEN
  CMWF DEBUG
  C        WRITE(6,*)'ELTRAK AFTER ERROR SUCCESS T= ',T,' RATIO= ',RATIO
  
  C
  C === EXAMINE THE COMPUTED ENDING LOCATION
  C
          XSI=0.0D0
          CALL INTRP123
       I      (MAXEQ,MAXND,NEQ,NODE, XOUT5, XW,
       O       DN,DJAC)
  
negative.code: C === EXAMINE THE VALUES OF DN
  C
  CMWF DEBUG
          IF (IDEBUG.GT.2) THEN
             WRITE(6,*)' ELTRAK EXAMINE DN, DN_S VALUES'
             WRITE(6,*)'DN= ',(DN(II),II=1,NODE)
             WRITE(6,*)'DN_S= ',(DN_S(II),II=1,NODE)
          ENDIF
  
  CMWF FLAG TO SAY THAT STEPPED THROUGH ELEMENT, MAKE 
  C     SURE RESTEP EVEN IF 
          ISTEPOUTSIDE = 0
          DO 150 I=1,NODE
  
  C
  