Merge tag '12.0-beta1' into jgrpp-beta

# Conflicts:
#	CMakeLists.txt
#	bin/ai/CMakeLists.txt
#	bin/game/CMakeLists.txt
#	src/build_vehicle_gui.cpp
#	src/console_cmds.cpp
#	src/core/overflowsafe_type.hpp
#	src/fios.cpp
#	src/lang/english.txt
#	src/lang/german.txt
#	src/lang/korean.txt
#	src/lang/polish.txt
#	src/network/core/game_info.cpp
#	src/network/core/game_info.h
#	src/network/core/tcp_game.cpp
#	src/network/core/tcp_game.h
#	src/network/network.cpp
#	src/network/network_client.cpp
#	src/network/network_client.h
#	src/network/network_coordinator.cpp
#	src/network/network_gui.cpp
#	src/network/network_server.cpp
#	src/network/network_server.h
#	src/newgrf_engine.cpp
#	src/openttd.cpp
#	src/rev.cpp.in
#	src/settings_type.h
#	src/train.h
#	src/train_cmd.cpp

src/train_cmd.cpp

@@ -264,6 +264,7 @@ void Train::ConsistChanged(ConsistChangeFlags allowed_changes)
 	this->tcache.cached_num_engines = 0;
 
 	bool train_can_tilt = true;
+	int min_curve_speed_mod = INT_MAX;
 
 	for (Train *u = this; u != nullptr; u = u->Next()) {
 		const RailVehicleInfo *rvi_u = RailVehInfo(u->engine_type);
@@ -303,6 +304,7 @@ void Train::ConsistChanged(ConsistChangeFlags allowed_changes)
 		const RailVehicleInfo *rvi_u = &e_u->u.rail;
 
 		if (!HasBit(e_u->info.misc_flags, EF_RAIL_TILTS)) train_can_tilt = false;
+		min_curve_speed_mod = std::min(min_curve_speed_mod, u->GetCurveSpeedModifier());
 
 		/* Cache wagon override sprite group. nullptr is returned if there is none */
 		u->tcache.cached_override = GetWagonOverrideSpriteSet(u->engine_type, u->cargo_type, u->gcache.first_engine);
@@ -389,6 +391,7 @@ void Train::ConsistChanged(ConsistChangeFlags allowed_changes)
 	/* store consist weight/max speed in cache */
 	this->vcache.cached_max_speed = max_speed;
 	this->tcache.cached_tflags = (train_can_tilt ? TCF_TILT : TCF_NONE);
+	this->tcache.cached_curve_speed_mod = min_curve_speed_mod;
 	this->tcache.cached_max_curve_speed = this->GetCurveSpeedLimit();
 
 	/* recalculate cached weights and power too (we do this *after* the rest, so it is known which wagons are powered and need extra weight added) */
@@ -666,6 +669,11 @@ int Train::GetCurveSpeedLimit() const
 			/* Apply max_speed bonus of 20% for a tilting train */
 			max_speed += max_speed / 5;
 		}
+
+		/* Apply max_speed modifier (cached value is fixed-point binary with 8 fractional bits)
+		 * and clamp the result to an acceptable range. */
+		max_speed += (max_speed * this->tcache.cached_curve_speed_mod) / 256;
+		max_speed = Clamp(max_speed, 2, absolute_max_speed);
 	}
 
 	return max_speed;