diff --git a/tubelib/node_states.lua b/tubelib/node_states.lua
index d305d5b..a863353 100644
--- a/tubelib/node_states.lua
+++ b/tubelib/node_states.lua
@@ -299,14 +299,15 @@ end
 -- To be called after successful node action to raise the timer
 -- and keep the node in state RUNNING
 function NodeStates:keep_running(pos, meta, val, num_items)
+	num_items = num_items or 1
 	-- set to RUNNING if not already done
 	self:start(pos, meta, true)
 	meta:set_int("tubelib_countdown", val)
 	meta:set_int("tubelib_item_meter", meta:get_int("tubelib_item_meter") + (num_items or 1))
 	if self.aging_level1 then
-		local cnt = meta:get_int("tubelib_aging") + (num_items or 1)
+		local cnt = meta:get_int("tubelib_aging") + num_items
 		meta:set_int("tubelib_aging", cnt)
-		if cnt > (self.aging_level1) and math.random(self.aging_level2) == 1 then
+		if cnt > (self.aging_level1) and math.random(self.aging_level2/num_items) == 1 then
 			self:defect(pos, meta)
 		end
 	end
diff --git a/tubelib_addons3/pushing_chest.lua b/tubelib_addons3/pushing_chest.lua
index 493b0a2..67b8aa9 100644
--- a/tubelib_addons3/pushing_chest.lua
+++ b/tubelib_addons3/pushing_chest.lua
@@ -14,6 +14,9 @@
 
 ]]--
 
+-- tubelib aging feature
+local AGING_LEVEL1 = 80 * tubelib.machine_aging_value
+local AGING_LEVEL2 = 240 * tubelib.machine_aging_value
 
 local Cache = {}
 
@@ -45,6 +48,17 @@ local function allow_metadata_inventory_move(pos, from_list, from_index, to_list
 	return count
 end	
 
+local function aging(pos, meta, num)
+	local cnt = meta:get_int("tubelib_aging") + num
+	meta:set_int("tubelib_aging", cnt)
+	if cnt > AGING_LEVEL1 and math.random(AGING_LEVEL2/num) == 1 then
+		minetest.get_node_timer(pos):stop()
+		local node = minetest.get_node(pos)
+		node.name = "tubelib_addons3:pushing_chest_defect"
+		minetest.swap_node(pos, node)
+	end
+end
+
 local function set_state(meta, state)
 	local number = meta:get_string("number")
 	meta:set_string("infotext", "HighPerf Pushing Chest "..number..": "..state)
@@ -83,6 +97,7 @@ local function shift_items(pos, elapsed)
 					stack = inv:get_stack("shift", idx)
 					stack:take_item(num)
 					inv:set_stack("shift", idx, stack)
+					aging(pos, meta, num)
 					return true
 				else
 					set_state(meta, "blocked")
@@ -174,6 +189,61 @@ minetest.register_node("tubelib_addons3:pushing_chest", {
 	sounds = default.node_sound_wood_defaults(),
 })
 
+minetest.register_node("tubelib_addons3:pushing_chest_defect", {
+	description = "HighPerf Pushing Chest",
+	tiles = {
+		-- up, down, right, left, back, front
+		'tubelib_pusher1.png^tubelib_addons3_node_frame4.png',
+		'tubelib_addons3_chest_bottom.png',
+		"tubelib_addons3_chest_out.png^tubelib_defect.png",
+		"tubelib_addons3_chest_side.png^tubelib_defect.png",
+		"tubelib_addons3_chest_side.png^tubelib_defect.png",
+		"tubelib_addons3_chest_front.png^tubelib_defect.png",
+	},
+
+	on_construct = function(pos)
+		local meta = minetest.get_meta(pos)
+		local inv = meta:get_inventory()
+		inv:set_size('main', 32)
+		inv:set_size('shift', 8)
+	end,
+	
+	after_place_node = function(pos, placer)
+		local meta = minetest.get_meta(pos)
+		local number = tubelib.add_node(pos, "tubelib_addons3:pushing_chest")	
+		meta:set_string("player_name", placer:get_player_name())
+		meta:set_string("number", number)
+		meta:set_string("formspec", formspec())
+		set_state(meta, "empty")
+	end,
+
+	can_dig = function(pos,player)
+		if minetest.is_protected(pos, player:get_player_name()) then
+			return false
+		end
+		local meta = minetest.get_meta(pos);
+		local inv = meta:get_inventory()
+		return inv:is_empty("main") and inv:is_empty("shift")
+	end,
+	
+	on_dig = function(pos, node, puncher, pointed_thing)
+		minetest.node_dig(pos, node, puncher, pointed_thing)
+	end,
+
+	allow_metadata_inventory_put = allow_metadata_inventory_put,
+	allow_metadata_inventory_take = allow_metadata_inventory_take,
+	allow_metadata_inventory_move = allow_metadata_inventory_move,
+
+	on_rotate = screwdriver.disallow,
+	
+	paramtype = "light",
+	sunlight_propagates = true,
+	paramtype2 = "facedir",
+	groups = {choppy=2, cracky=2, crumbly=2},
+	is_ground_content = false,
+	sounds = default.node_sound_wood_defaults(),
+})
+
 
 minetest.register_craft({
 	output = "tubelib_addons3:pushing_chest",
@@ -184,7 +254,8 @@ minetest.register_craft({
 	},
 })
 
-tubelib.register_node("tubelib_addons3:pushing_chest", {}, {
+tubelib.register_node("tubelib_addons3:pushing_chest", 
+	{"tubelib_addons3:pushing_chest_defect"}, {
 	on_recv_message = function(pos, topic, payload)
 		local node = minetest.get_node(pos)
 		if topic == "state" then
@@ -234,4 +305,17 @@ tubelib.register_node("tubelib_addons3:pushing_chest", {}, {
 	on_node_load = function(pos)
 		minetest.get_node_timer(pos):start(2)
 	end,
+	on_node_repair = function(pos)
+		local meta = minetest.get_meta(pos)
+		meta:set_int("tubelib_aging", 0)
+		meta:set_int("idx", 2)
+		
+		meta:set_string("formspec", formspec())
+		set_state(meta, "empty")
+		local node = minetest.get_node(pos)
+		node.name = "tubelib_addons3:pushing_chest"
+		minetest.swap_node(pos, node)
+		minetest.get_node_timer(pos):start(2)
+		return true
+	end,
 })	
diff --git a/tubelib_stairway/init.lua b/tubelib_stairway/init.lua
index 2e2fa50..114cbf1 100644
--- a/tubelib_stairway/init.lua
+++ b/tubelib_stairway/init.lua
@@ -11,7 +11,7 @@ minetest.register_node("tubelib_stairway:bridge1", {
 		fixed = {
 			{ 15/32, -17/32, -17/32,  17/32,  17/32, 17/32},
 			{-17/32, -17/32, -17/32, -15/32,  17/32, 17/32},
-			{-17/32, -17/32, -17/32,  17/32, -14/32, 17/32}
+			{-17/32, -15/32, -17/32,  17/32, -14/32, 17/32}
 		},
 	},
 
@@ -44,7 +44,7 @@ minetest.register_node("tubelib_stairway:bridge2", {
 		type = "fixed",
 		fixed = {
 			{-17/32, -17/32, -17/32, -15/32,  17/32, 17/32},
-			{-17/32, -17/32, -17/32,  17/32, -14/32, 17/32}
+			{-17/32, -15/32, -17/32,  17/32, -14/32, 17/32}
 		},
 	},
 
@@ -78,7 +78,7 @@ minetest.register_node("tubelib_stairway:bridge3", {
 			{-17/32, -17/32,  15/32,  17/32,  17/32, 17/32},
 			{ 15/32, -17/32, -17/32,  17/32,  17/32, 17/32},
 			{-17/32, -17/32, -17/32, -15/32,  17/32, 17/32},
-			{-17/32, -17/32, -17/32,  17/32, -14/32, 17/32}
+			{-17/32, -15/32, -17/32,  17/32, -14/32, 17/32}
 		},
 	},
 
@@ -111,7 +111,7 @@ minetest.register_node("tubelib_stairway:bridge4", {
 		fixed = {
 			{-17/32, -17/32,  15/32,  17/32,  17/32, 17/32},
 			{-17/32, -17/32, -17/32, -15/32,  17/32, 17/32},
-			{-17/32, -17/32, -17/32,  17/32, -14/32, 17/32}
+			{-17/32, -15/32, -17/32,  17/32, -14/32, 17/32}
 		},
 	},
 
diff --git a/tubelib_stairway/textures/tubelib_stairway_side.png b/tubelib_stairway/textures/tubelib_stairway_side.png
new file mode 100644
index 0000000..d28339a
Binary files /dev/null and b/tubelib_stairway/textures/tubelib_stairway_side.png differ