From: 1F616EMO <root@1f616emo.xyz>

This patch de-hardcodes that speed limit. To adapt the changes,
the following changes are made:

1. Added a setting key: advtrains_max_speed, acceppting integers from 1 to 99.
   Any values beyond the limit wil be capped.
2. Added max_speed = 20 m/s to the wagon metatable, so wagons not specifying a
   maximum speed continues to use 20 m/s.
3. Adjusted the train HUD so trains with maximum speed more than 20 m/s
   uses each segment to represent max / 20 m/s.
4. Adjusted speed target / limit / LZB indicators so they work well on the new
   segment bar
5. (Not so related) Out-of-bound LZB limitations are marked with a
   red arrow pointing right at where 20 m/s were.
---
 advtrains/init.lua         |  7 ++++++
 advtrains/settingtypes.txt |  3 +++
 advtrains/trainhud.lua     | 46 +++++++++++++++++++++++++++++++++-----
 advtrains/trainlogic.lua   |  2 +-
 advtrains/wagons.lua       |  1 +
 5 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/advtrains/init.lua b/advtrains/init.lua
index 06e456f..ba62c4a 100644
--- a/advtrains/init.lua
+++ b/advtrains/init.lua
@@ -66,6 +66,13 @@ if not advtrains.wagon_load_range then
 	advtrains.wagon_load_range = tonumber(minetest.settings:get("active_block_range"))*16
 end
 
+-- Maximum speed of trains
+-- The real maximum speed is the minimum value of all wagon's max speed and this value
+-- Default: 20; Min: 1; Max: 99
+-- Max. 99 because of the train HUD 7-seg display
+advtrains.TRAIN_MAX_SPEED = tonumber(minetest.settings:get("advtrains_max_speed")) or 20
+advtrains.TRAIN_MAX_SPEED = math.max(math.min(advtrains.TRAIN_MAX_SPEED, 99), 1)
+
 --pcall
 local no_action=false
 
diff --git a/advtrains/settingtypes.txt b/advtrains/settingtypes.txt
index 2b627cb..5b3aeff 100644
--- a/advtrains/settingtypes.txt
+++ b/advtrains/settingtypes.txt
@@ -61,3 +61,6 @@ advtrains_save_interval (Save Interval) int 60 20 3600
 #    If enabled, trains only collide with nodes with "normal" drawtype.
 advtrains_forgiving_collision (Forgiving Collision mode) bool false
 
+#    Maximum speed of all trains
+#    Set this to 0 to remove the cap entirely
+advtrains_max_speed (Maximum Train Speed) int 20 1 99
diff --git a/advtrains/trainhud.lua b/advtrains/trainhud.lua
index f9f4876..56a8de6 100644
--- a/advtrains/trainhud.lua
+++ b/advtrains/trainhud.lua
@@ -220,12 +220,35 @@ function advtrains.hud_train_format(train, flip)
 	hud:add_fill(215, 10, 15, 30, train.door_open==1 and "white" or "darkslategray"):add_fill(217, 12, 11, 11, "black")
 	-- speed indication(s)
 	hud:add_n7seg(320, 10, 110, 90, vel, 2, "red")
-	hud:add_segmentbar_leftright(10, 65, 217, 20, 3, 20, max, 20, "darkslategray", 0, vel, "white")
-	if res and res > 0 then
-		hud:add_fill(7+res*11, 60, 3, 30, "red")
+	do
+		local arrow_pos
+		if max > 20 then
+			arrow_pos = math.floor(vel * 20 / max)
+		else
+			arrow_pos = vel
+		end
+		hud:add_segmentbar_leftright(10, 65, 217, 20, 3, 20, math.min(max, 20), 20, "darkslategray", 0, arrow_pos, "white")
+	end
+	if res and res > 0 and res <= max then
+		print(res)
+		local arrow_pos
+		if max > 20 then
+			arrow_pos = 7 + math.floor(res * 220 / max)
+		else
+			arrow_pos = 7 + res * 11
+		end
+		hud:add_fill(arrow_pos, 60, 3, 30, "red")
 	end
 	if train.tarvelocity then
-		hud:add(1+train.tarvelocity*11, 85, T"advtrains_hud_arrow.png":transform"FY":multiply"cyan")
+		do
+			local arrow_pos
+			if max > 20 then
+				arrow_pos = 1 + train.tarvelocity * 220 / max
+			else
+				arrow_pos = 1 + train.tarvelocity * 11
+			end
+			hud:add(arrow_pos, 85, T"advtrains_hud_arrow.png":transform"FY":multiply"cyan")
+		end
 	end
 	local lzbdisp
 	local lzb = train.lzb
@@ -250,7 +273,20 @@ function advtrains.hud_train_format(train, flip)
 			local c = not spd and "lime" or (type(spd) == "number" and (spd == 0) and "red" or "orange") or nil
 			if c then
 				if spd and spd~=0 then
-					hud:add(1+spd*11, 50, T"advtrains_hud_arrow.png":multiply"red")
+					do
+						local texture = T"advtrains_hud_arrow.png":multiply"red"
+						if spd > max then
+							texture = texture:transform"R90"
+							spd = 20
+						end
+						local arrow_pos
+						if max > 20 then
+							arrow_pos = 1 + math.floor(spd * 220 / max)
+						else
+							arrow_pos = 1 + spd * 11
+						end
+						hud:add(arrow_pos, 50, texture)
+					end
 				end
 				local dist = math.floor(((oc[i].index or train.index)-train.index))
 				dist = math.max(0, math.min(999, dist))
diff --git a/advtrains/trainlogic.lua b/advtrains/trainlogic.lua
index f136577..0a3c6fe 100644
--- a/advtrains/trainlogic.lua
+++ b/advtrains/trainlogic.lua
@@ -1039,7 +1039,7 @@ function advtrains.update_trainpart_properties(train_id, invert_flipstate)
 	local train=advtrains.trains[train_id]
 	train.drives_on=advtrains.merge_tables(advtrains.all_tracktypes)
 	--FIX: deep-copy the table!!!
-	train.max_speed=20
+	train.max_speed=advtrains.TRAIN_MAX_SPEED
 	train.extent_h = 0;
 	
 	local rel_pos=0
diff --git a/advtrains/wagons.lua b/advtrains/wagons.lua
index 536c8d4..156db06 100644
--- a/advtrains/wagons.lua
+++ b/advtrains/wagons.lua
@@ -68,6 +68,7 @@ local wagon={
 	wagon_width=3, -- Wagon width in meters
 	has_inventory=false,
 	static_save=false,
+	max_speed = 20, -- Default value
 }
 
 
-- 
2.46.0