Add start-stop rail.

init.lua

@@ -249,8 +249,16 @@ function boost_cart.cart:on_step(dtime)
 		-- Slow down or speed up..
 		local acc = dir.y * -1.8
 
-		local speed_mod = tonumber(minetest.get_meta(pos):get_string("cart_acceleration"))
-		if speed_mod and speed_mod ~= 0 then
+		local speed_mod_string = minetest.get_meta(pos):get_string("cart_acceleration")
+		local speed_mod = tonumber(speed_mod_string)
+		if speed_mod_string == "halt" then
+			vel = {x=0, y=0, z=0}
+			acc = {x=0, y=0, z=0}
+			dir = {x=0, y=0, z=0}
+			pos = vector.round(pos)
+			update.pos = true
+			update.vel = true
+		elseif speed_mod and speed_mod ~= 0 then
 			if speed_mod > 0 then
 				for _,v in ipairs({"x","y","z"}) do
 					if math.abs(vel[v]) >= max_vel then
@@ -363,4 +371,4 @@ minetest.register_craft({
 		{"default:steel_ingot", "", "default:steel_ingot"},
 		{"default:steel_ingot", "default:steel_ingot", "default:steel_ingot"},
 	},
-})
+})

rails.lua

@@ -101,4 +101,34 @@ minetest.register_craft({
 		{"default:steel_ingot", "group:stick", "default:steel_ingot"},
 		{"default:steel_ingot", "default:coal_lump", "default:steel_ingot"},
 	}
-})
+})
+
+boost_cart:register_rail(":boost_cart:startstoprail", {
+	description = "Start-stop rail",
+	tiles = {"carts_rail_ss.png", "carts_rail_curved_ss.png", "carts_rail_t_junction_ss.png", "carts_rail_crossing_ss.png"},
+	groups = {dig_immediate = 2, attached_node = 1, rail = 1, connect_to_raillike = 1},
+
+	after_place_node = function(pos, placer, itemstack)
+		if not mesecon then
+			minetest.get_meta(pos):set_string("cart_acceleration", "halt")
+		end
+	end,
+
+	mesecons = {
+		effector = {
+			action_on = function(pos, node)
+				boost_cart:boost_rail(pos, 0.5)
+			end,
+
+			action_off = function(pos, node)
+				minetest.get_meta(pos):set_string("cart_acceleration", "halt")
+			end,
+		},
+	},
+})
+
+minetest.register_craft({
+	type = "shapeless",
+	output = "boost_cart:startstoprail 2",
+	recipe = {"carts:powerrail", "carts:brakerail"},
+})