diff --git a/advtrains.zip b/advtrains.zip
index 22c0e4d..226e34e 100644
Binary files a/advtrains.zip and b/advtrains.zip differ
diff --git a/advtrains/advtrains/signals.lua b/advtrains/advtrains/signals.lua
index ceb4166..a5a9aa3 100644
--- a/advtrains/advtrains/signals.lua
+++ b/advtrains/advtrains/signals.lua
@@ -41,8 +41,10 @@ for r,f in pairs({on={as="off", ls="green", als="red"}, off={as="on", ls="red",
 					advtrains.ndb.swap_node(pos, {name = "advtrains:retrosignal_"..f.as..rotation, param2 = node.param2})
 				end
 			}},
-			on_rightclick=function(pos, node, clicker)
-				advtrains.ndb.swap_node(pos, {name = "advtrains:retrosignal_"..f.as..rotation, param2 = node.param2})
+			on_rightclick=function(pos, node, player)
+				if minetest.check_player_privs(player:get_player_name(), {train_operator=true}) then
+					advtrains.ndb.swap_node(pos, {name = "advtrains:retrosignal_"..f.as..rotation, param2 = node.param2})
+				end
 			end,
 		})
 		advtrains.trackplacer.add_worked("advtrains:retrosignal", r, rotation, nil)
@@ -83,8 +85,10 @@ for r,f in pairs({on={as="off", ls="green", als="red"}, off={as="on", ls="red",
 					end
 				end,
 			},
-			on_rightclick=function(pos, node, clicker)
-				advtrains.ndb.swap_node(pos, {name = "advtrains:signal_"..f.as..rotation, param2 = node.param2})
+			on_rightclick=function(pos, node, player)
+				if minetest.check_player_privs(player:get_player_name(), {train_operator=true}) then
+					advtrains.ndb.swap_node(pos, {name = "advtrains:signal_"..f.as..rotation, param2 = node.param2})
+				end
 			end,
 		})
 		advtrains.trackplacer.add_worked("advtrains:signal", r, rotation, nil)
@@ -130,8 +134,10 @@ for r,f in pairs({on={as="off", ls="green", als="red"}, off={as="on", ls="red",
 					end
 				end,
 			},
-			on_rightclick=function(pos, node, clicker)
-				advtrains.ndb.swap_node(pos, {name = "advtrains:signal_wall_"..loc.."_"..f.as, param2 = node.param2})
+			on_rightclick=function(pos, node, player)
+				if minetest.check_player_privs(player:get_player_name(), {train_operator=true}) then
+					advtrains.ndb.swap_node(pos, {name = "advtrains:signal_wall_"..loc.."_"..f.as, param2 = node.param2})
+				end
 			end,
 		})
 	end
diff --git a/advtrains/advtrains/tracks.lua b/advtrains/advtrains/tracks.lua
index 90d2ad3..2bb61eb 100644
--- a/advtrains/advtrains/tracks.lua
+++ b/advtrains/advtrains/tracks.lua
@@ -260,11 +260,15 @@ advtrains.trackpresets = ap
 }]]
 function advtrains.register_tracks(tracktype, def, preset)
 	local function make_switchfunc(suffix_target, mesecon_state, is_state)
+		local rcswitchfunc=function(pos, node, player)
+			if minetest.check_player_privs(player:get_player_name(), {train_operator=true}) then
+				advtrains.ndb.swap_node(pos, {name=def.nodename_prefix.."_"..suffix_target, param2=node.param2})
+			end
+		end
 		local switchfunc=function(pos, node, newstate)
 			if newstate~=is_state then
 				advtrains.ndb.swap_node(pos, {name=def.nodename_prefix.."_"..suffix_target, param2=node.param2})
 			end
-			advtrains.invalidate_all_paths()
 		end
 		local mesec
 		if mesecon_state then -- if mesecons is not wanted, do not.
@@ -273,13 +277,13 @@ function advtrains.register_tracks(tracktype, def, preset)
 				rules=advtrains.meseconrules
 			}}
 		end
-		return switchfunc, mesec,
+		return rcswitchfunc, mesec,
 		{ 
 			getstate = is_state,
 			setstate = switchfunc,
 		}
 	end
-	local function make_overdef(suffix, rotation, conns, switchfunc, mesecontbl, luaautomation, in_creative_inv, drop_slope)
+	local function make_overdef(suffix, rotation, conns, rcswitchfunc, mesecontbl, luaautomation, in_creative_inv, drop_slope)
 		local img_suffix=suffix..rotation
 		return {
 			mesh = def.shared_model or (def.models_prefix.."_"..img_suffix..def.models_suffix),
@@ -293,7 +297,7 @@ function advtrains.register_tracks(tracktype, def, preset)
 			rely2=conns.rely2 or 0,
 			railheight=conns.railheight or 0,
 			
-			on_rightclick=switchfunc,
+			on_rightclick=rcswitchfunc,
 			groups = {
 				attached_node=1,
 				["advtrains_track_"..tracktype]=1,
@@ -352,9 +356,9 @@ function advtrains.register_tracks(tracktype, def, preset)
 	for suffix, conns in pairs(preset.variant) do
 		for rotid, rotation in ipairs(preset.rotation) do
 			if not def.formats[suffix] or def.formats[suffix][rotid] then
-				local switchfunc, mesecontbl, luaautomation
+				local rcswitchfunc, mesecontbl, luaautomation
 				if preset.switch[suffix] then
-					switchfunc, mesecontbl, luaautomation=make_switchfunc(preset.switch[suffix]..rotation, preset.switchmc[suffix], preset.switchst[suffix])
+					rcswitchfunc, mesecontbl, luaautomation=make_switchfunc(preset.switch[suffix]..rotation, preset.switchmc[suffix], preset.switchst[suffix])
 				end
 				local adef={}
 				if def.get_additional_definiton then
@@ -366,7 +370,7 @@ function advtrains.register_tracks(tracktype, def, preset)
 					make_overdef(
 						suffix, rotation,
 						cycle_conns(conns, rotid),
-						switchfunc, mesecontbl, luaautomation, preset.increativeinv[suffix], preset.slopenodes[suffix]
+						rcswitchfunc, mesecontbl, luaautomation, preset.increativeinv[suffix], preset.slopenodes[suffix]
 						),
 					adef
 					)
diff --git a/advtrains/advtrains/wagons.lua b/advtrains/advtrains/wagons.lua
index 28de3fa..15a0ec7 100644
--- a/advtrains/advtrains/wagons.lua
+++ b/advtrains/advtrains/wagons.lua
@@ -8,6 +8,11 @@ minetest.register_privilege("train_remove", {
 	description = "Player can remove trains not owned by player",
 	give_to_singleplayer= false,
 });
+minetest.register_privilege("train_operator", {
+	description = "Player may operate trains and switch signals. Given by default. Revoke to prevent players from griefing automated subway systems.",
+	give_to_singleplayer= true,
+	default= true,
+});
 
 local wagon={
 	collisionbox = {-0.5,-0.5,-0.5, 0.5,0.5,0.5},
@@ -242,7 +247,8 @@ function wagon:on_step(dtime)
 	--driver control
 	for seatno, seat in ipairs(self.seats) do
 		local driver=self.seatp[seatno] and minetest.get_player_by_name(self.seatp[seatno])
-		if seat.driving_ctrl_access and driver then
+		local has_driverstand=seat.driving_ctrl_access and self.seatp[seatno] and minetest.check_player_privs(self.seatp[seatno], {train_operator=true})
+		if has_driverstand and driver then
 			advtrains.update_driver_hud(driver:get_player_name(), self:train(), self.wagon_flipped)
 		elseif driver then
 			--only show the inside text
@@ -253,7 +259,7 @@ function wagon:on_step(dtime)
 			local pc=driver:get_player_control()
 			self.seatpc[seatno]=driver:get_player_control_bits()
 			
-			if seat.driving_ctrl_access then
+			if has_driverstand then
 				--regular driver stand controls
 				advtrains.on_control_change(pc, self:train(), self.wagon_flipped)
 			else