Refactors tram code to be more robust (#59596)

Tram code has a lot of locate() in list, a lot of unnecessary typechecking and generally bad practices. This refactors tramcode to be easily more maintainable and to have more consistent behaviour, as well as removing any unnecessary code.

code/game/objects/structures/industrial_lift.dm

@@ -172,6 +172,7 @@ GLOBAL_LIST_EMPTY(lifts)
 	if(!lift_master_datum)
 		lift_master_datum = new(src)
 
+
 /obj/structure/industrial_lift/proc/UncrossedRemoveItemFromLift(datum/source, atom/movable/potential_rider)
 	SIGNAL_HANDLER
 	RemoveItemFromLift(potential_rider)
@@ -411,14 +412,23 @@ GLOBAL_LIST_EMPTY(lifts)
 	var/initial_id = "middle_part"
 	var/obj/effect/landmark/tram/from_where
 	var/travel_direction
-	var/time_inbetween_moves = 1
 
+GLOBAL_DATUM(central_tram, /obj/structure/industrial_lift/tram/central)
+
+/obj/structure/industrial_lift/tram/Initialize(mapload)
+	. = ..()
+	return INITIALIZE_HINT_LATELOAD
 
 /obj/structure/industrial_lift/tram/central//that's a surprise tool that can help us later
 
 /obj/structure/industrial_lift/tram/central/Initialize(mapload)
+	if(GLOB.central_tram)
+		return INITIALIZE_HINT_QDEL
+
 	. = ..()
+
 	SStramprocess.can_fire = TRUE
+	GLOB.central_tram = src
 
 /obj/structure/industrial_lift/tram/LateInitialize()
 	. = ..()
@@ -435,20 +445,10 @@ GLOBAL_LIST_EMPTY(lifts)
  * even in the worst cast scenario.
  */
 /obj/structure/industrial_lift/tram/proc/find_our_location()
-	if(!from_where)
-		for(var/obj/effect/landmark/tram/our_location in GLOB.landmarks_list)
-			if(our_location.destination_id == initial_id)
-				from_where = our_location
-				break
-
-/obj/structure/industrial_lift/tram/central/find_our_location() //the tram knows where it is by knowing where it isn't
-	..()
-	for(var/location in lift_master_datum.lift_platforms)
-		var/obj/structure/industrial_lift/tram/tram_location = location
-		var/turf/turf = get_turf(src)
-		var/where_we_are = locate(/obj/effect/landmark/tram) in turf.contents
-		if(where_we_are)
-			tram_location.from_where = where_we_are //this gets set by the tram movement too but this actually makes sure we're at the dock we were moved to to prevent blender mode
+	for(var/obj/effect/landmark/tram/our_location as anything in GLOB.tram_landmarks)
+		if(our_location.destination_id == initial_id)
+			from_where = our_location
+			break
 
 /obj/structure/industrial_lift/tram/use(mob/user) //dont click the floor dingus we use computers now
 	return
@@ -469,18 +469,21 @@ GLOBAL_LIST_EMPTY(lifts)
  * literally ripping itself apart. The proc handles the first move before the subsystem
  * takes over to keep moving it in process()
  */
-/obj/structure/industrial_lift/tram/proc/tram_travel(obj/effect/landmark/tram/from_where, obj/effect/landmark/tram/to_where)
+/obj/structure/industrial_lift/tram/proc/tram_travel(obj/effect/landmark/tram/to_where)
+	if(to_where == from_where)
+		return
+
 	visible_message("<span class='notice'>[src] has been called to the [to_where]!</span")
 
 	lift_master_datum.set_controls(LOCKED)
+	travel_direction = get_dir(from_where, to_where)
+	travel_distance = get_dist(from_where, to_where)
+	//first movement is immediate
 	for(var/obj/structure/industrial_lift/tram/other_tram_part as anything in lift_master_datum.lift_platforms) //only thing everyone needs to know is the new location.
 		if(other_tram_part.travelling) //wee woo wee woo there was a double action queued. damn multi tile structs
 			return //we don't care to undo locked controls, though, as that will resolve itself
 		other_tram_part.travelling = TRUE
 		other_tram_part.from_where = to_where
-	travel_direction = get_dir(from_where, to_where)
-	travel_distance = get_dist(from_where, to_where)
-	//first movement is immediate
 	lift_master_datum.MoveLiftHorizontal(travel_direction, z)
 	travel_distance--
 
@@ -495,12 +498,12 @@ GLOBAL_LIST_EMPTY(lifts)
  */
 /obj/structure/industrial_lift/tram/proc/unlock_controls()
 	visible_message("<span class='notice'>[src]'s controls are now unlocked.</span")
-	for(var/lift in lift_master_datum.lift_platforms) //only thing everyone needs to know is the new location.
-		var/obj/structure/industrial_lift/tram/other_tram_part = lift
-		other_tram_part.travelling = FALSE
-		other_tram_part.find_our_location()
+	for(var/obj/structure/industrial_lift/tram/tram_part as anything in lift_master_datum.lift_platforms) //only thing everyone needs to know is the new location.
+		tram_part.travelling = FALSE
 		lift_master_datum.set_controls(UNLOCKED)
 
+GLOBAL_LIST_EMPTY(tram_landmarks)
+
 /obj/effect/landmark/tram
 	name = "tram destination" //the tram buttons will mention this.
 	icon_state = "tram"
@@ -508,6 +511,15 @@ GLOBAL_LIST_EMPTY(lifts)
 	///icons for the tgui console to list out for what is at this location
 	var/list/tgui_icons = list()
 
+/obj/effect/landmark/tram/Initialize()
+	. = ..()
+	GLOB.tram_landmarks += src
+
+/obj/effect/landmark/tram/Destroy()
+	GLOB.tram_landmarks -= src
+	return ..()
+
+
 /obj/effect/landmark/tram/left_part
 	name = "West Wing"
 	destination_id = "left_part"