diff --git a/siteupdate/cplusplus/classes/GraphGeneration/HGVertex.cpp b/siteupdate/cplusplus/classes/GraphGeneration/HGVertex.cpp
index 19d40279..9107f6f7 100644
--- a/siteupdate/cplusplus/classes/GraphGeneration/HGVertex.cpp
+++ b/siteupdate/cplusplus/classes/GraphGeneration/HGVertex.cpp
@@ -55,6 +55,8 @@ HGVertex::~HGVertex()
 {	//std::cout << "deleting vertex at " << first_waypoint->str() << std::endl;
 	while (incident_s_edges.size()) delete incident_s_edges.front();
 	while (incident_c_edges.size()) delete incident_c_edges.front();
+	while (incident_t_edges.size()) delete incident_t_edges.front();
 	delete[] s_vertex_num;
 	delete[] c_vertex_num;
+	delete[] t_vertex_num;
 }
diff --git a/siteupdate/cplusplus/classes/GraphGeneration/HighwayGraph.cpp b/siteupdate/cplusplus/classes/GraphGeneration/HighwayGraph.cpp
index 3dec1803..581070c8 100644
--- a/siteupdate/cplusplus/classes/GraphGeneration/HighwayGraph.cpp
+++ b/siteupdate/cplusplus/classes/GraphGeneration/HighwayGraph.cpp
@@ -165,7 +165,6 @@ inline void HighwayGraph::matching_vertices_and_edges
 	std::unordered_set<HGVertex*> rvset;	// union of all sets in regions
 	std::unordered_set<HGVertex*> svset;	// union of all sets in systems
 	std::unordered_set<HGVertex*> pvset;	// set of vertices within placeradius
-	std::unordered_set<TravelerList*> trav_set;
 
 	if (g.regions) for (Region *r : *g.regions)
 		rvset.insert(r->vertices.begin(), r->vertices.end());
@@ -231,7 +230,11 @@ inline void HighwayGraph::matching_vertices_and_edges
 			if (system_match)
 			{	mte.push_back(e);
 				e->t_written[threadnum] = 1;
-				for (TravelerList *t : e->segment->clinched_by) trav_set.insert(t);
+				for (TravelerList *t : e->segment->clinched_by)
+				  if (!t->in_subgraph[threadnum])
+				  {	traveler_lists.push_back(t);
+					t->in_subgraph[threadnum] = 1;
+				  }
 			}
 		    }
 		if (v->visibility < 2) continue;
@@ -252,7 +255,7 @@ inline void HighwayGraph::matching_vertices_and_edges
 			}
 		    }
 	}
-	traveler_lists.assign(trav_set.begin(), trav_set.end());
+	for (TravelerList* t : traveler_lists) t->in_subgraph[threadnum] = 0;
 	traveler_lists.sort(sort_travelers_by_name);
 }
 
diff --git a/siteupdate/cplusplus/classes/TravelerList/TravelerList.cpp b/siteupdate/cplusplus/classes/TravelerList/TravelerList.cpp
index e36471f8..d06d57eb 100644
--- a/siteupdate/cplusplus/classes/TravelerList/TravelerList.cpp
+++ b/siteupdate/cplusplus/classes/TravelerList/TravelerList.cpp
@@ -18,8 +18,10 @@ TravelerList::TravelerList(std::string travname, std::string* updarr[], ErrorLis
 	preview_systems_traveled = 0;
 	preview_systems_clinched = 0;
 	unsigned int list_entries = 0;
+	in_subgraph = new bool[args->numthreads];
 	traveler_num = new unsigned int[args->numthreads];
 		       // deleted on termination of program
+	for (size_t i = 0; i < args->numthreads; i++) in_subgraph[i] = 0;
 	traveler_name = travname.substr(0, travname.size()-5); // strip ".list" from end of travname
 	if (traveler_name.size() > DBFieldLength::traveler)
 	  el->add_error("Traveler name " + traveler_name + " > " + std::to_string(DBFieldLength::traveler) + "bytes");
diff --git a/siteupdate/cplusplus/classes/TravelerList/TravelerList.h b/siteupdate/cplusplus/classes/TravelerList/TravelerList.h
index 4ad02d54..b89d78e6 100644
--- a/siteupdate/cplusplus/classes/TravelerList/TravelerList.h
+++ b/siteupdate/cplusplus/classes/TravelerList/TravelerList.h
@@ -30,6 +30,7 @@ class TravelerList
 	std::unordered_map<Region*, double> active_only_mileage_by_region;				// total mileage per region, active only
 	std::unordered_map<HighwaySystem*, std::unordered_map<Region*, double>> system_region_mileages;	// mileage per region per system
 	std::unordered_set<Route*> routes;
+	bool* in_subgraph;
 	unsigned int *traveler_num;
 	unsigned int active_systems_traveled;
 	unsigned int active_systems_clinched;