diff --git a/editormode.cpp b/editormode.cpp
index 71e14e96..ef9b897f 100644
--- a/editormode.cpp
+++ b/editormode.cpp
@@ -300,6 +300,7 @@ editor_mode::on_mouse_button( int const Button, int const Action, int const Mods
 					if (!cloned)
 						return;
 
+					cloned->mark_dirty();
 					cloned->location(Camera.Pos + GfxRenderer.Mouse_Position());
 					simulation::Instances.insert(cloned);
 					simulation::Region->insert(cloned);
diff --git a/sceneeditor.cpp b/sceneeditor.cpp
index 99513935..6b730a83 100644
--- a/sceneeditor.cpp
+++ b/sceneeditor.cpp
@@ -40,6 +40,7 @@ basic_editor::translate( scene::basic_node *Node, glm::dvec3 const &Location, bo
     // NOTE: bit of a waste for single nodes, for the sake of less varied code down the road
     auto const translation { targetlocation - initiallocation };
 
+	Node->mark_dirty();
     if( Node->group() == null_handle ) {
         translate_node( Node, Node->location() + translation );
     }
diff --git a/scenenode.h b/scenenode.h
index ba5a38c0..18da3158 100644
--- a/scenenode.h
+++ b/scenenode.h
@@ -345,6 +345,10 @@ public:
         group( scene::group_handle Group );
     scene::group_handle
         group() const;
+	void
+	    mark_dirty() { m_dirty = true; }
+	bool
+	    dirty() const { return m_dirty; }
 
 protected:
 // members
@@ -354,6 +358,7 @@ protected:
     double m_rangesquaredmax { 0.0 }; // visibility range, max
     bool m_visible { true }; // visibility flag
     std::string m_name;
+	bool m_dirty { false };
 
 private:
 // methods
diff --git a/scenenodegroups.cpp b/scenenodegroups.cpp
index 58031caf..f45c5ecb 100644
--- a/scenenodegroups.cpp
+++ b/scenenodegroups.cpp
@@ -119,24 +119,38 @@ node_groups::insert( scene::group_handle const Group, basic_event *Event ) {
 
 // sends basic content of the class in legacy (text) format to provided stream
 void
-node_groups::export_as_text( std::ostream &Output ) const {
+node_groups::export_as_text( std::ostream &Output, bool Dirty ) const {
 
     for( auto const &group : m_groupmap ) {
-
-        Output << "group\n";
+		bool any = false;
         for( auto *node : group.second.nodes ) {
+			if (node->dirty() != Dirty)
+				continue;
             // HACK: auto-generated memory cells aren't exported, so we check for this
             // TODO: is_exportable as basic_node method
             if( ( typeid( *node ) == typeid( TMemCell ) )
              && ( false == static_cast<TMemCell *>( node )->is_exportable ) ) {
                 continue;
             }
+
+			if (!any)
+				Output << "group\n";
+			any = true;
+
             node->export_as_text( Output );
         }
         for( auto *event : group.second.events ) {
+			if (Dirty)
+				continue;
+
+			if (!any)
+				Output << "group\n";
+			any = true;
+
             event->export_as_text( Output );
         }
-        Output << "endgroup\n";
+		if (any)
+			Output << "endgroup\n";
     }
 }
 
diff --git a/scenenodegroups.h b/scenenodegroups.h
index d0815bae..9f040409 100644
--- a/scenenodegroups.h
+++ b/scenenodegroups.h
@@ -48,7 +48,7 @@ public:
             return m_groupmap[ Group ]; }
     // sends basic content of the class in legacy (text) format to provided stream
     void
-        export_as_text( std::ostream &Output ) const;
+	    export_as_text(std::ostream &Output , bool Dirty) const;
 
 private:
 // types
diff --git a/simulationstateserializer.cpp b/simulationstateserializer.cpp
index a601893c..7294ab27 100644
--- a/simulationstateserializer.cpp
+++ b/simulationstateserializer.cpp
@@ -952,7 +952,7 @@ state_serializer::transform( glm::dvec3 Location, scene::scratch_data const &Scr
 
 // stores class data in specified file, in legacy (text) format
 void
-state_serializer::export_as_text( std::string const &Scenariofile ) const {
+state_serializer::export_as_text(std::string const &Scenariofile) const {
 
     if( Scenariofile == "$.scn" ) {
         ErrorLog( "Bad file: scenery export not supported for file \"$.scn\"" );
@@ -961,66 +961,79 @@ state_serializer::export_as_text( std::string const &Scenariofile ) const {
         WriteLog( "Scenery data export in progress..." );
     }
 
-    auto filename { Scenariofile };
-    while( filename[ 0 ] == '$' ) {
+	auto filename { Scenariofile };
+	while( filename[ 0 ] == '$' ) {
         // trim leading $ char rainsted utility may add to the base name for modified .scn files
-        filename.erase( 0, 1 );
+		filename.erase( 0, 1 );
     }
-    erase_extension( filename );
-    filename = Global.asCurrentSceneryPath + filename + "_export";
+	erase_extension( filename );
+	auto absfilename = Global.asCurrentSceneryPath + filename + "_export";
 
-    std::ofstream scmfile { filename + ".scm" };
-    // groups
-    scmfile << "// groups\n";
-    scene::Groups.export_as_text( scmfile );
-    // tracks
-    scmfile << "// paths\n";
-    for( auto const *path : Paths.sequence() ) {
-        if( path->group() == null_handle ) {
-            path->export_as_text( scmfile );
-        }
-    }
-    // traction
-    scmfile << "// traction\n";
-    for( auto const *traction : Traction.sequence() ) {
-        if( traction->group() == null_handle ) {
-            traction->export_as_text( scmfile );
-        }
-    }
-    // power grid
-    scmfile << "// traction power sources\n";
-    for( auto const *powersource : Powergrid.sequence() ) {
-        if( powersource->group() == null_handle ) {
-            powersource->export_as_text( scmfile );
-        }
-    }
-    // models
-    scmfile << "// instanced models\n";
-    for( auto const *instance : Instances.sequence() ) {
-        if( instance->group() == null_handle ) {
-            instance->export_as_text( scmfile );
-        }
-    }
-    // sounds
-    // NOTE: sounds currently aren't included in groups
-    scmfile << "// sounds\n";
-    Region->export_as_text( scmfile );
+	std::ofstream scmdirtyfile { absfilename + "_dirty.scm" };
+	export_nodes_to_stream(scmdirtyfile, true);
 
-    std::ofstream ctrfile { filename + ".ctr" };
-    // mem cells
-    ctrfile << "// memory cells\n";
-    for( auto const *memorycell : Memory.sequence() ) {
-        if( ( true == memorycell->is_exportable )
-         && ( memorycell->group() == null_handle ) ) {
-            memorycell->export_as_text( ctrfile );
-        }
-    }
-    // events
-    Events.export_as_text( ctrfile );
+	std::ofstream scmfile { absfilename + ".scm" };
+	export_nodes_to_stream(scmfile, false);
+
+	// sounds
+	// NOTE: sounds currently aren't included in groups
+	scmfile << "// sounds\n";
+	Region->export_as_text( scmfile );
+
+	scmfile << "// modified objects\ninclude " << filename << "_export_dirty.scm\n";
+
+	std::ofstream ctrfile { absfilename + ".ctr" };
+	// mem cells
+	ctrfile << "// memory cells\n";
+	for( auto const *memorycell : Memory.sequence() ) {
+		if( ( true == memorycell->is_exportable )
+		 && ( memorycell->group() == null_handle ) ) {
+			memorycell->export_as_text( ctrfile );
+		}
+	}
+
+	// events
+	Events.export_as_text( ctrfile );
 
     WriteLog( "Scenery data export done." );
 }
 
+void
+state_serializer::export_nodes_to_stream(std::ostream &scmfile, bool Dirty) const {
+	// groups
+	scmfile << "// groups\n";
+	scene::Groups.export_as_text( scmfile, Dirty );
+
+	// tracks
+	scmfile << "// paths\n";
+	for( auto const *path : Paths.sequence() ) {
+		if( path->dirty() == Dirty && path->group() == null_handle ) {
+			path->export_as_text( scmfile );
+		}
+	}
+	// traction
+	scmfile << "// traction\n";
+	for( auto const *traction : Traction.sequence() ) {
+		if( traction->dirty() == Dirty && traction->group() == null_handle ) {
+			traction->export_as_text( scmfile );
+		}
+	}
+	// power grid
+	scmfile << "// traction power sources\n";
+	for( auto const *powersource : Powergrid.sequence() ) {
+		if( powersource->dirty() == Dirty && powersource->group() == null_handle ) {
+			powersource->export_as_text( scmfile );
+		}
+	}
+	// models
+	scmfile << "// instanced models\n";
+	for( auto const *instance : Instances.sequence() ) {
+		if( instance && instance->dirty() == Dirty && instance->group() == null_handle ) {
+			instance->export_as_text( scmfile );
+		}
+	}
+}
+
 } // simulation
 
   //---------------------------------------------------------------------------
diff --git a/simulationstateserializer.h b/simulationstateserializer.h
index 5a55bfe3..a73b858a 100644
--- a/simulationstateserializer.h
+++ b/simulationstateserializer.h
@@ -40,7 +40,7 @@ public:
 	    deserialize_continue(std::shared_ptr<deserializer_state> state);
     // stores class data in specified file, in legacy (text) format
     void
-        export_as_text( std::string const &Scenariofile ) const;
+	    export_as_text(std::string const &Scenariofile) const;
 
 	// temporary public for editor
 	TAnimModel * deserialize_model( cParser &Input, scene::scratch_data &Scratchpad, scene::node_data const &Nodedata );
@@ -79,6 +79,7 @@ private:
     void skip_until( cParser &Input, std::string const &Token );
     // transforms provided location by specifed rotation and offset
     glm::dvec3 transform( glm::dvec3 Location, scene::scratch_data const &Scratchpad );
+	void export_nodes_to_stream(std::ostream &, bool Dirty) const;
 };
 
 } // simulation