diff --git a/src/group.h b/src/group.h
index a6c46d84ae..3886b155c4 100644
--- a/src/group.h
+++ b/src/group.h
@@ -24,15 +24,12 @@ extern GroupPool _group_pool; ///< Pool of groups.
 struct GroupStatistics {
 	Money profit_last_year;                 ///< Sum of profits for all vehicles.
 	Money profit_last_year_min_age;         ///< Sum of profits for vehicles considered for profit statistics.
-	uint16_t *num_engines;                    ///< Caches the number of engines of each type the company owns.
+	std::map<EngineID, uint16_t> num_engines; ///< Caches the number of engines of each type the company owns.
 	uint16_t num_vehicle;                     ///< Number of vehicles.
 	uint16_t num_vehicle_min_age;             ///< Number of vehicles considered for profit statistics;
 	bool autoreplace_defined;               ///< Are any autoreplace rules set?
 	bool autoreplace_finished;              ///< Have all autoreplacement finished?
 
-	GroupStatistics();
-	~GroupStatistics();
-
 	void Clear();
 
 	void ClearProfits()
@@ -49,6 +46,8 @@ struct GroupStatistics {
 		this->autoreplace_finished = false;
 	}
 
+	uint16_t GetNumEngines(EngineID engine) const;
+
 	static GroupStatistics &Get(CompanyID company, GroupID id_g, VehicleType type);
 	static GroupStatistics &Get(const Vehicle *v);
 	static GroupStatistics &GetAllGroup(const Vehicle *v);
diff --git a/src/group_cmd.cpp b/src/group_cmd.cpp
index b0091ab303..bc379e3212 100644
--- a/src/group_cmd.cpp
+++ b/src/group_cmd.cpp
@@ -27,16 +27,6 @@
 GroupPool _group_pool("Group");
 INSTANTIATE_POOL_METHODS(Group)
 
-GroupStatistics::GroupStatistics()
-{
-	this->num_engines = CallocT<uint16_t>(Engine::GetPoolSize());
-}
-
-GroupStatistics::~GroupStatistics()
-{
-	free(this->num_engines);
-}
-
 /**
  * Clear all caches.
  */
@@ -47,9 +37,20 @@ void GroupStatistics::Clear()
 	this->num_vehicle_min_age = 0;
 	this->profit_last_year_min_age = 0;
 
-	/* This is also called when NewGRF change. So the number of engines might have changed. Reallocate. */
-	free(this->num_engines);
-	this->num_engines = CallocT<uint16_t>(Engine::GetPoolSize());
+	/* This is also called when NewGRF change. So the number of engines might have changed. Reset. */
+	this->num_engines.clear();
+}
+
+/**
+ * Get number of vehicles of a specific engine ID.
+ * @param engine Engine ID.
+ * @returns number of vehicles of this engine ID.
+ */
+uint16_t GroupStatistics::GetNumEngines(EngineID engine) const
+{
+	auto found = this->num_engines.find(engine);
+	if (found != std::end(this->num_engines)) return found->second;
+	return 0;
 }
 
 /**
@@ -800,7 +801,7 @@ uint GetGroupNumEngines(CompanyID company, GroupID id_g, EngineID id_e)
 	for (const Group *g : Group::Iterate()) {
 		if (g->parent == id_g) count += GetGroupNumEngines(company, g->index, id_e);
 	}
-	return count + GroupStatistics::Get(company, id_g, e->type).num_engines[id_e];
+	return count + GroupStatistics::Get(company, id_g, e->type).GetNumEngines(id_e);
 }
 
 /**
diff --git a/src/script/api/script_engine.cpp b/src/script/api/script_engine.cpp
index c142c5fd30..088b692925 100644
--- a/src/script/api/script_engine.cpp
+++ b/src/script/api/script_engine.cpp
@@ -32,7 +32,7 @@
 	/* AIs have only access to engines they can purchase or still have in use.
 	 * Deity has access to all engined that will be or were available ever. */
 	CompanyID company = ScriptObject::GetCompany();
-	return ScriptCompanyMode::IsDeity() || ::IsEngineBuildable(engine_id, e->type, company) || ::Company::Get(company)->group_all[e->type].num_engines[engine_id] > 0;
+	return ScriptCompanyMode::IsDeity() || ::IsEngineBuildable(engine_id, e->type, company) || ::Company::Get(company)->group_all[e->type].GetNumEngines(engine_id) > 0;
 }
 
 /* static */ bool ScriptEngine::IsBuildable(EngineID engine_id)