Can't score the primary particles by BEAMPART(210) in subroutine of BXDRAW in mgdraw.f?

Dear FLUKA experts,
          The primary particle is proton. I want to score the primary
particles by using the mgdraw.f, but I score nothing by the following
code in BXDRAW,

        IF( JTRACK.EQ.210) THEN
          IF(ETRACK.GT.AM(JTRACK)) THEN
            TPPTRACK = ETRACK - AM(JTRACK)

            IF(MREG.EQ.3 .AND. NEWREG.EQ.4) THEN

               WRITE(62,200) XSCO,YSCO, PTRACK, WTRACK

            ENDIF

          ENDIF
        ENDIF

If I score the proton (namely JTRACK.EQ. 1), everything is OK. How can
separate the primary protons and produced protons in BXDRAW?
        Thank you very much!

-- 
With my best regards,
                               Hantao Jing