Add Automatic Train Control system

advtrains/api_doc.txt

@@ -103,7 +103,7 @@ minetest.register_node(nodename, {
 	after_place_node=function(pos)
 		advtrains.reset_trackdb_position(pos)
 	end,
-	^- the code in these 3 functions is required for advtrains to work.
+	^- the code in these 3 default minetest API functions is required for advtrains to work, however you can add your own code
 	
 	advtrains = {
 		on_train_enter=function(pos, train_id) end

advtrains/atc.lua

@@ -1,4 +1,294 @@
 --atc.lua
 --registers and controls the ATC system
 
---(simple)mesecon detector rails
+local atc={}
+-- ATC persistence table
+atc.controllers = {}
+--contents: {command="...", arrowconn=0-15 where arrow points}
+
+advtrains.fpath_atc=minetest.get_worldpath().."/advtrains_atc"
+local file, err = io.open(advtrains.fpath_atc, "r")
+if not file then
+	local er=err or "Unknown Error"
+	print("[advtrains]Failed loading advtrains atc save file "..er)
+else
+	local tbl = minetest.deserialize(file:read("*a"))
+	if type(tbl) == "table" then
+		atc.controllers=tbl.controllers
+	end
+	file:close()
+end
+function atc.save()
+	--leave space for more save data.
+	local datastr = minetest.serialize({controllers = atc.controllers})
+	if not datastr then
+		minetest.log("error", "[advtrains] Failed to serialize trackdb data!")
+		return
+	end
+	local file, err = io.open(advtrains.fpath_atc, "w")
+	if err then
+		return err
+	end
+	file:write(datastr)
+	file:close()
+end
+
+--call from advtrains.detector subprogram
+
+function atc.trigger_controller_train_enter(pos, train_id)
+	atc.send_command(pos)
+end
+
+--general
+
+function atc.send_command(pos)
+	local pts=minetest.pos_to_string(pos)
+	if atc.controllers[pts] then
+		print("Called send_command at "..pts)
+		local train_id = advtrains.detector.on_node[pts]
+		if train_id then
+			if advtrains.trains[train_id] then
+				print("send_command inside if: "..sid(train_id))
+				atc.train_reset_command(train_id)
+				local arrowconn=atc.controllers[pts].arrowconn
+				local train=advtrains.trains[train_id]
+				for index, ppos in pairs(train.path) do
+					if vector.equals(advtrains.round_vector_floor_y(ppos), pos) then
+						advtrains.trains[train_id].atc_arrow =
+								vector.equals(
+										advtrains.dirCoordSet(pos, arrowconn),
+										advtrains.round_vector_floor_y(train.path[index+train.movedir])
+								)
+						advtrains.trains[train_id].atc_command=atc.controllers[pts].command
+						print("Sending ATC Command: "..atc.controllers[pts].command)
+					end
+				end
+			end
+		end
+	end
+	return false
+end
+
+function atc.train_reset_command(train_id)
+	advtrains.trains[train_id].atc_command=nil
+	advtrains.trains[train_id].atc_delay=0
+	advtrains.trains[train_id].atc_brake_target=nil
+	advtrains.trains[train_id].atc_wait_finish=nil
+	advtrains.trains[train_id].atc_arrow=nil
+end
+
+--nodes
+local idxtrans={static=1, mesecon=2, digiline=3}
+local apn_func=function(pos)
+	advtrains.reset_trackdb_position(pos)
+	local meta=minetest.get_meta(pos)
+	if meta then
+		meta:set_string("infotext", "ATC controller, unconfigured.")
+		meta:set_string("formspec", atc.get_atc_controller_formspec(pos, meta))
+	end
+end
+
+advtrains.register_tracks("default", {
+	nodename_prefix="advtrains:dtrack_atc",
+	texture_prefix="advtrains_dtrack_atc",
+	models_prefix="advtrains_dtrack_detector",
+	models_suffix=".b3d",
+	shared_texture="advtrains_dtrack_rail_atc.png",
+	description="ATC controller",
+	formats={},
+	get_additional_definiton = function(def, preset, suffix, rotation)
+		return {
+			after_place_node=apn_func,
+			on_place_rail=apn_func,
+			after_dig_node=function(pos)
+				advtrains.invalidate_all_paths()
+				advtrains.reset_trackdb_position(pos)
+				local pts=minetest.pos_to_string(pos)
+				atc.controllers[pts]=nil
+			end,
+			on_receive_fields = function(pos, formname, fields, player)
+				if minetest.is_protected(pos, player:get_player_name()) then
+					minetest.chat_send_player(player:get_player_name(), "This position is protected!")
+					return
+				end
+				local meta=minetest.get_meta(pos)
+				if meta then
+					if not fields.save then 
+						--maybe only the dropdown changed
+						if fields.mode then
+							meta:set_string("mode", idxtrans[fields.mode])
+							meta:set_string("infotext", "ATC controller, mode "..fields.mode.."\n"..( fields.mode=="digiline" and "Channel: "..meta:get_string("channel") or "Command: "..meta:get_string("command") ) )
+							meta:set_string("formspec", atc.get_atc_controller_formspec(pos, meta))
+						end
+						return
+					end
+					meta:set_string("mode", idxtrans[fields.mode])
+					meta:set_string("command", fields.command)
+					meta:set_string("command_on", fields.command_on)
+					meta:set_string("channel", fields.channel)
+					meta:set_string("infotext", "ATC controller, mode "..fields.mode.."\n"..( fields.mode=="digiline" and "Channel: "..meta:get_string("channel") or "Command: "..meta:get_string("command") ) )
+					meta:set_string("formspec", atc.get_atc_controller_formspec(pos, meta))
+					
+					local pts=minetest.pos_to_string(pos)
+					local _, conn1=advtrains.get_rail_info_at(pos, advtrains.all_tracktypes)
+					atc.controllers[pts]={command=fields.command, arrowconn=conn1}
+					atc.send_command(pos)
+				end
+			end,
+		}
+	end
+}, advtrains.trackpresets.t_30deg_straightonly)
+
+
+function atc.get_atc_controller_formspec(pos, meta)
+	local mode=tonumber(meta:get_string("mode")) or 1
+	local command=meta:get_string("command")
+	local command_on=meta:get_string("command_on")
+	local channel=meta:get_string("channel")
+	local formspec="size[8,6]"..
+		"dropdown[0,0;3;mode;static,mesecon,digiline;"..mode.."]"
+	if mode<3 then
+		formspec=formspec.."field[0.5,1.5;7,1;command;Command;"..minetest.formspec_escape(command).."]"
+		if tonumber(mode)==2 then
+			formspec=formspec.."field[0.5,3;7,1;command_on;Command (on);"..minetest.formspec_escape(command_on).."]"
+		end
+	else
+		formspec=formspec.."field[0.5,1.5;7,1;channel;Digiline channel;"..minetest.formspec_escape(channel).."]"
+	end
+	return formspec.."button_exit[0.5,4.5;7,1;save;Save]"
+end
+
+--from trainlogic.lua train step
+local matchptn={
+	["SM"]=function(id, train)
+		train.tarvelocity=train.max_speed
+		return 2
+	end,
+	["S([0-9]+)"]=function(id, train, match)
+		train.tarvelocity=tonumber(match)
+		return #match+1
+	end,
+	["B([0-9]+)"]=function(id, train, match)
+		if train.velocity>tonumber(match) then
+			train.atc_brake_target=tonumber(match)
+			if train.tarvelocity>train.atc_brake_target then
+				train.tarvelocity=train.atc_brake_target
+			end
+		end
+		return #match+1
+	end,
+	["W"]=function(id, train)
+		train.atc_wait_finish=true
+		return 1
+	end,
+	["D([0-9]+)"]=function(id, train, match)
+		train.atc_delay=tonumber(match)
+		return #match+1
+	end,
+	["R"]=function(id, train)
+		if train.velocity<=0 then
+			train.movedir=train.movedir*-1
+			train.atc_arrow = not train.atc_arrow
+		else
+			print("ATC Reverse command warning: didn't reverse train!")
+		end
+		return 1
+	end,
+}
+
+function atc.execute_atc_command(id, train)
+	--strip whitespaces
+	local command=string.match(train.atc_command, "^%s*(.*)$")
+	
+	
+	if string.match(command, "^%s*$") then
+		train.atc_command=nil
+		return
+	end
+	--conditional statement?
+	local is_cond, cond_applies
+	local cond, rest=string.match(command, "^I([%+%-])(.+)$")
+	if cond then
+		is_cond=true
+		if cond=="+" then
+			cond_applies=train.atc_arrow
+		end
+		if cond=="-" then
+			cond_applies=not train.atc_arrow
+		end
+	else 
+		cond, compare, rest=string.match(command, "^I([<>]=?)([0-9]+)(.+)$")
+		if cond and compare then
+			is_cond=true
+			if cond=="<" then
+				cond_applies=train.velocity<tonumber(compare)
+			end
+			if cond==">" then
+				cond_applies=train.velocity>tonumber(compare)
+			end
+			if cond=="<=" then
+				cond_applies=train.velocity<=tonumber(compare)
+			end
+			if cond==">=" then
+				cond_applies=train.velocity>=tonumber(compare)
+			end
+		end
+	end	
+	if is_cond then
+		print("Evaluating if statement: "..command)
+		print("Cond: "..(cond or "nil"))
+		print("Applies: "..(cond_applies and "true" or "false"))
+		print("Rest: "..rest)
+		--find end of conditional statement
+		local nest, pos, elsepos=0, 1
+		while nest>=0 do
+			if pos>#rest then
+				print("ATC command syntax error: I statement not closed: "..command)
+				atc.train_reset_command(id)
+				return
+			end
+			local char=string.sub(rest, pos, pos)
+			if char=="I" then
+				nest=nest+1
+			end
+			if char==";" then
+				nest=nest-1
+			end
+			if nest==0 and char=="E" then
+				elsepos=pos+0
+			end
+			pos=pos+1
+		end
+		if not elsepos then elsepos=pos-1 end
+		if cond_applies then
+			command=string.sub(rest, 1, elsepos-1)..string.sub(rest, pos)
+		else
+			command=string.sub(rest, elsepos+1, pos-2)..string.sub(rest, pos)
+		end
+		print("Result: "..command)
+		train.atc_command=command
+		atc.execute_atc_command(id, train)
+		return
+	else
+		for pattern, func in pairs(matchptn) do
+			local match=string.match(command, "^"..pattern)
+			if match then
+				local patlen=func(id, train, match)
+				
+				print("Executing: "..string.sub(command, 1, patlen))
+				
+				train.atc_command=string.sub(command, patlen+1)
+				if train.atc_delay<=0 and not train.atc_wait_finish then
+					--continue (recursive, cmds shouldn't get too long, and it's a end-recursion.)
+					atc.execute_atc_command(id, train)
+				end
+				return
+			end
+		end
+	end
+	print("ATC command parse error: "..command)
+	atc.train_reset_command(id)
+end
+
+--move table to desired place
+advtrains.atc=atc

advtrains/atc_command.txt

@@ -0,0 +1,68 @@
+ATC Command Syntax
+
+A train runs the current ATC command once it receives it, including delayed instructions. If the train receives a new command, the current command is discarded.
+Spaces can be inserted into commands as needed and are ignored.
+
+# simple commands:
+
+S<[0-9]+ speed or 'M'>
+Set target speed of train to <speed>. Accelerates if slower, rolls if faster. 'M' means maximum speed.
+Execution of command continues immediately.
+
+B<[0-9]+ speed>
+Brake until speed is reached. If faster, apply brakes, if slower, do nothing.
+Execution of command continues immediately.
+
+Examples:
+SM : accelerate to maximum speed
+S0 : roll to stand
+B0 : brake to stand
+S0B3 or B3S0: brake to 3, then roll to stand.
+
+W
+Wait until S and/or B commands reached the desired speed before continuing execution.
+
+D<[0-9]+ time>
+Delay: Wait for time seconds before continuing execution.
+
+R
+Reverse: change movement direction of train. ONLY WORKS WHEN TRAIN STANDS, else no-op.
+Use B0WR to definitely change direction.
+
+Examples:
+B0 W R D10 SM
+Subway train stopping in dead end station and returning in opposite direction
+
+# conditional statements:
+
+I<condition><code>;
+Execute code only if condition applies
+I<condition><code1>E<code2>;
+Execute code1 only if condition applies, else execute code2
+
+Conditions:
++ / -
+Tests the train's movement direction against the arrow on the ATC rail: M+ is true when train drives in direction of arrow.
+
+[</>/<=/>=][speed]
+Test if train's speed is greater or smaller than the given value
+
+Examples:
+I- B0 W R ; S8
+If the train drives in the 'wrong' direction, stop and reverse; independently accelerate to speed 8 afterwards.
+
+I<8 S8 ;
+If the train is slower than 8, accelerate to 8.
+
+# ATC controller operation modes
+static: Only give 1 static command.
+mesecon: Give 2 different commands depending on if the controller is mesecon-powered or not
+digiline: Don't give any commands by itself. When a train passes, a digiline message in the form of "[+/-][speed]" is sent on the set channel (where +/- means the same as with conditions). Any digiline message sent to the controller will be interpreted as ATC command and sent to the train.
+
+# Persistence
+ATC controllers that are configured as 'static' or 'mesecon' are persistent over mapblock unloads and will even command the train when the mapblock is unloaded. This is not possible with digilines since these do not work in unloaded mapchunks.
+
+# LUA ATC controller (in development)
+The LUA ATC Controller will operate by using LUA code. All operations shown above will have a function equivalent. Additionally all LUA ATC controllers share an environment and setting signal and switch status will be possible to allow for complicated railway systems/fully automated subways a.s.o.
+Also planned:
+- digicompute add-on to allow computer access to the ATC environment (railway maps... ... ... ... ...)

advtrains/trackplacer.lua

@@ -129,7 +129,7 @@ function tp.bend_rail(originpos, conn, nnpref)
 		return false
 	end
 end
-function tp.placetrack(pos, nnpref)
+function tp.placetrack(pos, nnpref, placer, itemstack, pointed_thing)
 	--1. find all rails that are likely to be connected
 	local tr=tp.tracks[nnpref]
 	local p_rails={}
@@ -140,9 +140,16 @@ function tp.placetrack(pos, nnpref)
 	end
 	if #p_rails==0 then
 		minetest.set_node(pos, {name=nnpref.."_"..tr.default})
+		if minetest.registered_nodes[nnpref.."_"..tr.default] and minetest.registered_nodes[nnpref.."_"..tr.default].after_place_node then
+			minetest.registered_nodes[nnpref.."_"..tr.default].after_place_node(pos, placer, itemstack, pointed_thing)
+		end
 	elseif #p_rails==1 then
 		tp.bend_rail(pos, p_rails[1], nnpref)
 		minetest.set_node(pos, tr.single_conn[p_rails[1]])
+		local nname=tr.single_conn[p_rails[1]].name
+		if minetest.registered_nodes[nname] and minetest.registered_nodes[nname].after_place_node then
+			minetest.registered_nodes[nname].after_place_node(pos, placer, itemstack, pointed_thing)
+		end
 	else
 		--iterate subsets
 		for k1, conn1 in ipairs(p_rails) do
@@ -152,6 +159,10 @@ function tp.placetrack(pos, nnpref)
 						tp.bend_rail(pos, conn1, nnpref)
 						tp.bend_rail(pos, conn2, nnpref)
 						minetest.set_node(pos, tr.double_conn[conn1.."_"..conn2])
+						local nname=tr.double_conn[conn1.."_"..conn2].name
+						if minetest.registered_nodes[nname] and minetest.registered_nodes[nname].after_place_node then
+							minetest.registered_nodes[nname].after_place_node(pos, placer, itemstack, pointed_thing)
+						end
 						return
 					end
 				end
@@ -160,6 +171,10 @@ function tp.placetrack(pos, nnpref)
 		--not found
 		tp.bend_rail(pos, p_rails[1], nnpref)
 		minetest.set_node(pos, tr.single_conn[p_rails[1]])
+		local nname=tr.single_conn[p_rails[1]].name
+		if minetest.registered_nodes[nname] and minetest.registered_nodes[nname].after_place_node then
+			minetest.registered_nodes[nname].after_place_node(pos, placer, itemstack, pointed_thing)
+		end
 	end
 end
 
@@ -183,7 +198,7 @@ function tp.register_track_placer(nnprefix, imgprefix, dispname)
 				end
 				if minetest.registered_nodes[minetest.get_node(pos).name] and minetest.registered_nodes[minetest.get_node(pos).name].buildable_to
 					and minetest.registered_nodes[minetest.get_node(upos).name] and minetest.registered_nodes[minetest.get_node(upos).name].walkable then
-					tp.placetrack(pos, nnprefix)
+					tp.placetrack(pos, nnprefix, placer, itemstack, pointed_thing)
 					if not minetest.setting_getbool("creative_mode") then
 						itemstack:take_item()
 					end
@@ -230,7 +245,7 @@ minetest.register_craftitem("advtrains:trackworker",{
 			local modext=tp.tracks[nnprefix].twrotate[suffix]
 
 			if rotation==modext[#modext] then --increase param2
-				minetest.set_node(pos, {name=nnprefix.."_"..suffix..modext[1], param2=(node.param2+1)%4})
+				minetest.swap_node(pos, {name=nnprefix.."_"..suffix..modext[1], param2=(node.param2+1)%4})
 				return
 			else
 				local modpos
@@ -239,7 +254,7 @@ minetest.register_craftitem("advtrains:trackworker",{
 						minetest.chat_send_player(placer:get_player_name(), "This node can't be rotated using the trackworker!")
 					return
 				end
-				minetest.set_node(pos, {name=nnprefix.."_"..suffix..modext[modpos+1], param2=node.param2})
+				minetest.swap_node(pos, {name=nnprefix.."_"..suffix..modext[modpos+1], param2=node.param2})
 			end
 			advtrains.invalidate_all_paths()
 		end
@@ -269,7 +284,7 @@ minetest.register_craftitem("advtrains:trackworker",{
 			  end
 		    end
 			local nextsuffix=tp.tracks[nnprefix].twcycle[suffix]
-			minetest.set_node(pos, {name=nnprefix.."_"..nextsuffix..rotation, param2=node.param2})
+			minetest.swap_node(pos, {name=nnprefix.."_"..nextsuffix..rotation, param2=node.param2})
 			--invalidate trains
 			advtrains.invalidate_all_paths()
 		else

advtrains/tracks.lua

@@ -36,7 +36,8 @@ advtrains.all_tracktypes={}
 --definition preparation
 local function conns(c1, c2, r1, r2, rh, rots) return {conn1=c1, conn2=c2, rely1=r1, rely2=r2, railheight=rh} end
 
-local t_30deg={
+local ap={}
+ap.t_30deg={
 	regstep=1,
 	variant={
 		st=conns(0,8),
@@ -110,7 +111,7 @@ local t_30deg={
 	rotation={"", "_30", "_45", "_60"},
 	increativeinv={},
 }
-local t_30deg_straightonly={
+ap.t_30deg_straightonly={
 	regstep=1,
 	variant={
 		st=conns(0,8),
@@ -135,7 +136,7 @@ local t_30deg_straightonly={
 	rotation={"", "_30", "_45", "_60"},
 	increativeinv={st},
 }
-local t_30deg_straightonly_noplacer={
+ap.t_30deg_straightonly_noplacer={
 	regstep=1,
 	variant={
 		st=conns(0,8),
@@ -160,7 +161,7 @@ local t_30deg_straightonly_noplacer={
 	rotation={"", "_30", "_45", "_60"},
 	increativeinv={st},
 }
-local t_45deg={
+ap.t_45deg={
 	regstep=2,
 	variant={
 		st=conns(0,8),
@@ -215,6 +216,7 @@ local t_45deg={
 	rotation={"", "_45"},
 	increativeinv={vst1=true, vst2=true}
 }
+advtrains.trackpresets = ap
 
 --definition format: ([] optional)
 --[[{
@@ -302,6 +304,9 @@ function advtrains.register_tracks(tracktype, def, preset)
 		after_place_node=function(pos)
 			advtrains.reset_trackdb_position(pos)
 		end,
+		on_place_rail=function(pos)
+			advtrains.reset_trackdb_position(pos)
+		end,
 	}, def.common or {})
 	--make trackplacer base def
 	advtrains.trackplacer.register_tracktype(def.nodename_prefix, preset.tpdefault)
@@ -386,10 +391,10 @@ advtrains.detector.clean_step_before = false
 --The entry already being contained in advtrains.detector.on_node_restore will not trigger an on_train_enter event on the node.  (when path is reset, this is saved).
 function advtrains.detector.enter_node(pos, train_id)
 	local pts = minetest.pos_to_string(advtrains.round_vector_floor_y(pos))
-	print("enterNode "..pts.." "..sid(train_id))
+	--print("enterNode "..pts.." "..sid(train_id))
 	if advtrains.detector.on_node[pts] then
 		if advtrains.trains[advtrains.detector.on_node[pts]] then
-			print(""..pts.." already occupied")
+			--print(""..pts.." already occupied")
 			return false
 		else
 			advtrains.detector.leave_node(pos, advtrains.detector.on_node[pts])
@@ -405,9 +410,9 @@ function advtrains.detector.enter_node(pos, train_id)
 end
 function advtrains.detector.leave_node(pos, train_id)
 	local pts = minetest.pos_to_string(advtrains.round_vector_floor_y(pos))
-	print("leaveNode "..pts.." "..sid(train_id))
+	--print("leaveNode "..pts.." "..sid(train_id))
 	if not advtrains.detector.on_node[pts] then
-		print(""..pts.." leave: nothing here")
+		--print(""..pts.." leave: nothing here")
 		return false
 	end
 	if advtrains.detector.on_node[pts]==train_id then
@@ -415,7 +420,7 @@ function advtrains.detector.leave_node(pos, train_id)
 		advtrains.detector.on_node[pts]=nil
 	else
 		if advtrains.trains[advtrains.detector.on_node[pts]] then
-			print(""..pts.." occupied by another train")
+			--print(""..pts.." occupied by another train")
 			return false
 		else
 			advtrains.detector.leave_node(pos, advtrains.detector.on_node[pts])
@@ -446,7 +451,10 @@ function advtrains.detector.call_enter_callback(pos, train_id)
 	local mregnode=minetest.registered_nodes[node.name]
 	if mregnode and mregnode.advtrains and mregnode.advtrains.on_train_enter then
 		mregnode.advtrains.on_train_enter(pos, train_id)
-	end 
+	end
+	
+	--atc code wants to be notified too
+	advtrains.atc.trigger_controller_train_enter(pos, train_id)
 end
 function advtrains.detector.call_leave_callback(pos, train_id)
 	--print("instructed to call leave calback")
@@ -576,7 +584,7 @@ advtrains.register_tracks("regular", {
 	shared_model="trackplane.b3d",
 	description="Deprecated Track",
 	formats={vst1={}, vst2={}},
-}, t_45deg)
+}, ap.t_45deg)
 
 
 advtrains.register_tracks("default", {
@@ -587,7 +595,7 @@ advtrains.register_tracks("default", {
 	shared_texture="advtrains_dtrack_rail.png",
 	description="Track",
 	formats={vst1={true, false, true}, vst2={true, false, true}, vst31={true}, vst32={true}, vst33={true}},
-}, t_30deg)
+}, ap.t_30deg)
 
 --bumpers
 advtrains.register_tracks("default", {
@@ -598,7 +606,7 @@ advtrains.register_tracks("default", {
 	shared_texture="advtrains_dtrack_rail.png",
 	description="Bumper",
 	formats={},
-}, t_30deg_straightonly)
+}, ap.t_30deg_straightonly)
 --legacy bumpers
 for _,rot in ipairs({"", "_30", "_45", "_60"}) do
 	minetest.register_alias("advtrains:dtrack_bumper"..rot, "advtrains:dtrack_bumper_st"..rot)
@@ -629,7 +637,7 @@ if mesecon then
 				}
 			}
 		end
-	}, t_30deg_straightonly)
+	}, ap.t_30deg_straightonly)
 	advtrains.register_tracks("default", {
 		nodename_prefix="advtrains:dtrack_detector_on",
 		texture_prefix="advtrains_dtrack_detector",
@@ -654,7 +662,7 @@ if mesecon then
 				}
 			}
 		end
-	}, t_30deg_straightonly_noplacer)
+	}, ap.t_30deg_straightonly_noplacer)
 end
 --TODO legacy
 --I know lbms are better for this purpose

advtrains/trainhud.lua

@@ -11,7 +11,7 @@ local mletter={[1]="F", [-1]="R", [0]="N"}
 function advtrains.on_control_change(pc, train, flip)
 	if pc.sneak then
 		if pc.up then
-			train.tarvelocity = advtrains.all_traintypes[train.traintype].max_speed or 10
+			train.tarvelocity = train.max_speed or 10
 		end
 		if pc.down then
 			train.tarvelocity = 0

advtrains/trainlogic.lua

@@ -119,6 +119,7 @@ advtrains.save = function()
 	file:close()
 	
 	advtrains.save_trackdb()
+	advtrains.atc.save()
 end
 minetest.register_on_shutdown(advtrains.save)
 
@@ -302,6 +303,24 @@ function advtrains.train_step(id, train, dtime)
 	if train.locomotives_in_train==0 then
 		train.tarvelocity=0
 	end
+	
+	--interpret ATC command
+	if train.atc_brake_target and train.atc_brake_target>=train.velocity then
+		train.atc_brake_target=nil
+	end
+	if train.atc_wait_finish then
+		if not train.atc_brake_target and train.velocity==train.tarvelocity then
+			train.atc_wait_finish=nil
+		end
+	end
+	if train.atc_command then
+		if train.atc_delay<=0 and not train.atc_wait_finish then
+			advtrains.atc.execute_atc_command(id, train)
+		else
+			train.atc_delay=train.atc_delay-dtime
+		end
+	end
+	
 	--make brake adjust the tarvelocity if necessary
 	if train.brake and (math.ceil(train.velocity)-1)<train.tarvelocity then
 		train.tarvelocity=math.max((math.ceil(train.velocity)-1), 0)
@@ -318,7 +337,7 @@ function advtrains.train_step(id, train, dtime)
 			if front_off_track or back_off_track or train.recently_collided_with_env then --every wagon has a brake, so not divided by mass.
 				--print("braking with emergency force")
 				applydiff= -(math.min((advtrains.train_emerg_force*dtime), math.abs(diff)))
-			elseif train.brake then
+			elseif train.brake or (train.atc_brake_target and train.atc_brake_target<train.velocity) then
 				--print("braking with default force")
 				--no math.min, because it can grow beyond tarvelocity, see up there
 				--dont worry, it will never fall below zero.