diff --git a/moses/TranslationModel/UG/mm/ug_ttrack_base.cc b/moses/TranslationModel/UG/mm/ug_ttrack_base.cc
index 60d20a5f9..e754539f6 100644
--- a/moses/TranslationModel/UG/mm/ug_ttrack_base.cc
+++ b/moses/TranslationModel/UG/mm/ug_ttrack_base.cc
@@ -36,6 +36,13 @@ namespace ugdiss
     return buf.str();
   }
 
+  size_t 
+  len_from_pid(uint64_t pid)
+  {
+    static uint64_t two16 = uint64_t(1)<<16;
+    return pid%two16;
+  }
+
 #if 0
   template<>
   string
diff --git a/moses/TranslationModel/UG/mm/ug_ttrack_base.h b/moses/TranslationModel/UG/mm/ug_ttrack_base.h
index 9668bee0e..fbbc131ad 100644
--- a/moses/TranslationModel/UG/mm/ug_ttrack_base.h
+++ b/moses/TranslationModel/UG/mm/ug_ttrack_base.h
@@ -26,6 +26,8 @@ namespace ugdiss
 
   typedef boost::dynamic_bitset<uint64_t> bdBitset;
 
+  size_t len_from_pid(uint64_t pid);
+
   template<typename sid_t, typename off_t, typename len_t>
   void
   parse_pid(uint64_t const pid, sid_t & sid,