add option to show train and wagon id

advtrains/settingtypes.txt

@@ -1,7 +1,6 @@
-#    Disable the train collision behavior. Trains will never collide and just drive through each other.
-#    Note that this makes coupling trains impossible, and introduces 'interesting' behavior with detector and ATC rails.
-#    Also, it is very hard to separate two subway trains that are stuck inside each other, since it can be impossible to access the driver seat.
-advtrains_disable_collisions (Disable train collisions) bool false
+#    Display train and wagon ID in the infotext of trains.
+#    Useful when working with LuaATC or while debugging.
+advtrains_show_ids (Show ID's in infotext) bool false
 #    Enable the debug ring buffer
 #    This has no effect on the user experience, except decreased performance. Debug outputs are saved in a ring buffer to be printed when an error occurs.
 #    You probably want to leave this setting set to false.

advtrains/wagons.lua

@@ -11,6 +11,8 @@ advtrains.wagons = {}
 advtrains.wagon_prototypes = {}
 advtrains.wagon_objects = {}
 
+local setting_show_ids = minetest.settings:get_bool("advtrains_show_ids")
+
 --
 function advtrains.create_wagon(wtype, owner)
 	local new_id=advtrains.random_id()
@@ -285,6 +287,9 @@ function wagon:on_step(dtime)
 		
 		--check infotext
 		local outside=self:train().text_outside or ""
+		if setting_show_ids then
+			outside = outside .. "\nT:" .. data.train_id .. " W:" .. self.id
+		end
 		
 		local train=self:train()
 		--show off-track information in outside text instead of notifying the whole server about this