diff --git a/src/constants.F90 b/src/constants.F90
index e9688e761d..8887e1fc9b 100644
--- a/src/constants.F90
+++ b/src/constants.F90
@@ -363,6 +363,7 @@ module constants
   integer, parameter :: UNIT_STATE    = 16 ! unit # for writing state point
   integer, parameter :: CMFD_BALANCE  = 17 ! unit # for writing cmfd balance file
   integer, parameter :: UNIT_PARTICLE = 18 ! unit # for writing particle restart
+  integer, parameter :: UNIT_TRACK    = 19 ! unit # for writing particle tracks
 
   !=============================================================================
   ! CMFD CONSTANTS
diff --git a/src/physics.F90 b/src/physics.F90
index 707049b1a8..e1c7f12c32 100644
--- a/src/physics.F90
+++ b/src/physics.F90
@@ -73,6 +73,12 @@ contains
     ! Force calculation of cross-sections by setting last energy to zero 
     micro_xs % last_E = ZERO
 
+    if (run_mode == MODE_PARTICLE) then
+      open(UNIT=UNIT_TRACK, FILE='test', STATUS='replace', &
+           ACCESS='stream')
+      write(UNIT_TRACK) p % coord0 % xyz
+    end if
+
     do while (p % alive)
 
       ! Calculate microscopic and macroscopic cross sections -- note: if the
@@ -100,6 +106,10 @@ contains
         coord % xyz = coord % xyz + distance * coord % uvw
         coord => coord % next
       end do
+      
+      if (run_mode == MODE_PARTICLE) then
+        write(UNIT_TRACK) p % coord0 % xyz
+      end if
 
       ! Score track-length tallies
       if (active_tracklength_tallies % size() > 0) &
@@ -175,6 +185,10 @@ contains
 
     end do
 
+    if (run_mode == MODE_PARTICLE) then
+      close(UNIT=UNIT_TRACK)
+    end if
+
   end subroutine transport
 
 !===============================================================================