diff --git a/advtrains/occupation.lua b/advtrains/occupation.lua
index dd0235a..568f308 100644
--- a/advtrains/occupation.lua
+++ b/advtrains/occupation.lua
@@ -208,7 +208,7 @@ function o.get_occupations(train, index)
 	return r, pos
 end
 -- Gets a mapping of train id's to indexes of trains that stand or drive over
--- returns (table with train_id->index), position
+-- returns (table with train_id->index)
 function o.get_trains_at(ppos)
 	local pos = advtrains.round_vector_floor_y(ppos)
 	local t = occget(pos)
@@ -226,4 +226,22 @@ function o.get_trains_at(ppos)
 	return r
 end
 
+-- Gets a mapping of train id's to indexes of trains that have a path
+-- generated over this node
+-- returns (table with train_id->index)
+function o.get_trains_over(ppos)
+	local pos = advtrains.round_vector_floor_y(ppos)
+	local t = occget(pos)
+	if not t then return {} end
+	local r = {}
+	local i = 1
+	while t[i] do
+		local train = advtrains.trains[t[i]]
+		local idx = t[i+1]
+		r[t[i]] = idx
+		i = i + 2
+	end
+	return r
+end
+
 advtrains.occ = o
diff --git a/advtrains/trainlogic.lua b/advtrains/trainlogic.lua
index f26f7da..7147787 100644
--- a/advtrains/trainlogic.lua
+++ b/advtrains/trainlogic.lua
@@ -1037,26 +1037,23 @@ function advtrains.get_train_at_pos(pos)
 	end
 end
 
+
+-- ehm... I never adapted this function to the new path system ?!
 function advtrains.invalidate_all_paths(pos)
-	--if a position is given, only invalidate inside a radius to save performance
-	local inv_radius=50
-	atprint("invalidating all paths")
-	for k,v in pairs(advtrains.trains) do
-		local exec=true
-		if pos and v.path and v.index and v.end_index then
-			--start and end pos of the train
-			local cmp1=v.path[atround(v.index)]
-			local cmp2=v.path[atround(v.end_index)]
-			if vector.distance(pos, cmp1)>inv_radius and vector.distance(pos, cmp2)>inv_radius then
-				exec=false
-			end
-		end
-		if exec then
-			advtrains.invalidate_path(k)
-		end
+	local tab
+	if pos then
+		-- if position given, check occupation system
+		tab = advtrains.occ.get_trains_over(pos)
+	else
+		tab = advtrains.trains
+	end
+	
+	for id, _ in pairs(tab) do
+		advtrains.invalidate_path(id)
 	end
 end
 function advtrains.invalidate_path(id)
+	atdebug("Path invalidate:",id)
 	local v=advtrains.trains[id]
 	if not v then return end
 	advtrains.path_invalidate(v)
diff --git a/advtrains_interlocking/database.lua b/advtrains_interlocking/database.lua
index af90880..a2df111 100644
--- a/advtrains_interlocking/database.lua
+++ b/advtrains_interlocking/database.lua
@@ -105,6 +105,7 @@ local signal_assignments = {}
 -- track+direction -> signal position
 local influence_points = {}
 
+
 function ildb.load(data)
 	if not data then return end
 	if data.tcbs then
@@ -119,6 +120,9 @@ function ildb.load(data)
 	if data.rs_locks then
 		advtrains.interlocking.route.rte_locks = data.rs_locks
 	end
+	if data.rs_callbacks then
+		advtrains.interlocking.route.rte_callbacks = data.rs_callbacks
+	end
 	if data.influence_points then
 		influence_points = data.influence_points
 	end
@@ -130,6 +134,7 @@ function ildb.save()
 		ts=track_sections,
 		signalass = signal_assignments,
 		rs_locks = advtrains.interlocking.route.rte_locks,
+		rs_callbacks = advtrains.interlocking.route.rte_callbacks,
 		influence_points = influence_points,
 	}
 end
diff --git a/advtrains_interlocking/lzb.lua b/advtrains_interlocking/lzb.lua
index c9e40ab..8781d40 100644
--- a/advtrains_interlocking/lzb.lua
+++ b/advtrains_interlocking/lzb.lua
@@ -177,14 +177,22 @@ local function apply_control(id, train)
 	train.ctrl.lzb = nil
 end
 
-
-advtrains.te_register_on_new_path(function(id, train)
+local function invalidate(train)
 	train.lzb = {
 		trav = atfloor(train.index),
 		travsht = train.is_shunt,
 		oncoming = {}
 	}
 	train.ctrl.lzb = nil
+end
+
+function advtrains.interlocking.lzb_invalidate(train)
+	invalidate(train)
+end
+
+
+advtrains.te_register_on_new_path(function(id, train)
+	invalidate(train)
 	look_ahead(id, train)
 end)
 
diff --git a/advtrains_interlocking/signal_api.lua b/advtrains_interlocking/signal_api.lua
index 90fe1fc..3a042c0 100644
--- a/advtrains_interlocking/signal_api.lua
+++ b/advtrains_interlocking/signal_api.lua
@@ -66,9 +66,10 @@ advtrains = {
 		
 		-- The aspect passed in here can always be queried using the
 		-- advtrains.interlocking.signal_get_supposed_aspect(pos) function.
+		-- It is always DANGER when the signal is not used as route signal.
 		
 		-- For static signals, this function should be completely omitted
-		-- If this function is ommitted, it won't be possible to use
+		-- If this function is omitted, it won't be possible to use
 		-- route setting on this signal.
 	end
 	function get_aspect(pos, node)
@@ -89,6 +90,18 @@ after_dig_node = advtrains.interlocking.signal_after_dig
 
 (If you need to specify custom can_dig or after_dig_node callbacks,
 please call those functions anyway!)
+
+Important note: If your signal should support external ways to set its
+aspect (e.g. via mesecons), there are some things that need to be considered:
+- advtrains.interlocking.signal_get_supposed_aspect(pos) won't respect this
+- Whenever you change the signal aspect, and that aspect change
+did not happen through a call to
+advtrains.interlocking.signal_set_aspect(pos, asp), you are
+*required* to call this function:
+advtrains.interlocking.signal_on_aspect_changed(pos)
+in order to notify trains about the aspect change.
+This function will query get_aspect to retrieve the new aspect.
+
 ]]--
 
 local DANGER = {
@@ -128,6 +141,22 @@ function advtrains.interlocking.signal_set_aspect(pos, asp)
 	local ndef=minetest.registered_nodes[node.name]
 	if ndef and ndef.advtrains and ndef.advtrains.set_aspect then
 		ndef.advtrains.set_aspect(pos, node, asp)
+		advtrains.interlocking.signal_on_aspect_changed(pos)
+	end
+end
+
+-- should be called when aspect has changed on this signal.
+function advtrains.interlocking.signal_on_aspect_changed(pos)
+	local ipts, iconn = advtrains.interlocking.db.get_ip_by_signalpos(pos)
+	if not ipts then return end
+	local ipos = minetest.string_to_pos(ipts)
+	
+	local tns = advtrains.occ.get_trains_over(ipos)
+	for id, sidx in pairs(tns) do
+		local train = advtrains.trains[id]
+		if train.index <= sidx then
+			advtrains.interlocking.lzb_invalidate(train)
+		end
 	end
 end