Apply ATC speed restriction as advisory to prevent instant braking

Remove redundant function

src/train.h

@@ -191,7 +191,6 @@ struct Train FINAL : public GroundVehicle<Train, VEH_TRAIN> {
 	};
 
 private:
-	int GetAtcMaxSpeed() const;
 	MaxSpeedInfo GetCurrentMaxSpeedInfoInternal(bool update_state) const;
 
 public:

src/train_cmd.cpp

@@ -993,18 +993,6 @@ static void AdvanceLookAheadPosition(Train *v)
 	}
 }
 
-/**
- * Calculates the maximum speed based on any train in front of this train.
- */
-int32 Train::GetAtcMaxSpeed() const
-{
-	if (!(this->vehstatus & VS_CRASHED) && this->signal_speed_restriction != 0) {
-		return std::max<int32>(25, this->signal_speed_restriction);
-	}
-
-	return INT32_MAX;
-}
-
 /**
  * Calculates the maximum speed information of the vehicle under its current conditions.
  * @return Maximum speed information of the vehicle.
@@ -1015,8 +1003,6 @@ Train::MaxSpeedInfo Train::GetCurrentMaxSpeedInfoInternal(bool update_state) con
 			this->gcache.cached_max_track_speed :
 			std::min<int>(this->tcache.cached_max_curve_speed, this->gcache.cached_max_track_speed);
 
-	if (_settings_game.vehicle.train_speed_adaptation) max_speed = std::min<int>(max_speed, GetAtcMaxSpeed());
-
 	if (this->current_order.IsType(OT_LOADING_ADVANCE)) max_speed = std::min(max_speed, 15);
 
 	int advisory_max_speed = max_speed;
@@ -1080,6 +1066,9 @@ Train::MaxSpeedInfo Train::GetCurrentMaxSpeedInfoInternal(bool update_state) con
 	if (this->speed_restriction != 0) {
 		advisory_max_speed = std::min<int>(advisory_max_speed, this->speed_restriction);
 	}
+	if (this->signal_speed_restriction != 0 && _settings_game.vehicle.train_speed_adaptation) {
+		advisory_max_speed = std::min<int>(advisory_max_speed, this->signal_speed_restriction);
+	}
 	if (this->reverse_distance > 1) {
 		advisory_max_speed = std::min<int>(advisory_max_speed, ReversingDistanceTargetSpeed(this));
 	}