diff --git a/src/strings.cpp b/src/strings.cpp
index 5dbeccd04f..5c8ec2369e 100644
--- a/src/strings.cpp
+++ b/src/strings.cpp
@@ -58,9 +58,7 @@ TextDirection _current_text_dir; ///< Text direction of the currently selected l
 std::unique_ptr<icu::Collator> _current_collator;    ///< Collator for the language currently in use.
 #endif /* WITH_ICU_I18N */
 
-static uint64 _global_string_params_data[20];     ///< Global array of string parameters. To access, use #SetDParam.
-static WChar _global_string_params_type[20];      ///< Type of parameters stored in #_global_string_params
-StringParameters _global_string_params(_global_string_params_data, 20, _global_string_params_type);
+AllocatedStringParameters _global_string_params(20);
 
 /**
  * Prepare the string parameters for the next formatting run. This means
@@ -905,12 +903,8 @@ static void FormatString(StringBuilder &builder, const char *str_arg, StringPara
 		args.SetTypeOfNextParameter(b);
 		switch (b) {
 			case SCC_ENCODED: {
-				uint64 sub_args_data[20];
-				WChar sub_args_type[20];
 				bool sub_args_need_free[20];
-				StringParameters sub_args(sub_args_data, 20, sub_args_type);
-
-				sub_args.PrepareForNextRun(); // Needed to reset the currently undefined types
+				AllocatedStringParameters sub_args(20);
 				memset(sub_args_need_free, 0, sizeof(sub_args_need_free));
 
 				char *p;
@@ -1400,9 +1394,7 @@ static void FormatString(StringBuilder &builder, const char *str_arg, StringPara
 			case SCC_DEPOT_NAME: { // {DEPOT}
 				VehicleType vt = (VehicleType)args.GetInt32();
 				if (vt == VEH_AIRCRAFT) {
-					uint64 args_array[] = {(uint64)args.GetInt32()};
-					WChar types_array[] = {SCC_STATION_NAME};
-					StringParameters tmp_params(args_array, 1, types_array);
+					StringParameters tmp_params = StringParameters(args, 1);
 					GetStringWithArgs(builder, STR_FORMAT_DEPOT_NAME_AIRCRAFT, tmp_params);
 					break;
 				}
@@ -1437,9 +1429,7 @@ static void FormatString(StringBuilder &builder, const char *str_arg, StringPara
 						assert(grffile != nullptr);
 
 						StartTextRefStackUsage(grffile, 6);
-						uint64 tmp_dparam[6] = { 0 };
-						WChar tmp_type[6] = { 0 };
-						StringParameters tmp_params(tmp_dparam, 6, tmp_type);
+						AllocatedStringParameters tmp_params(6);
 						GetStringWithArgs(builder, GetGRFStringID(grffile->grfid, 0xD000 + callback), tmp_params);
 						StopTextRefStackUsage();
 
@@ -1536,9 +1526,7 @@ static void FormatString(StringBuilder &builder, const char *str_arg, StringPara
 						}
 					}
 
-					uint64 args_array[] = {STR_TOWN_NAME, st->town->index, st->index};
-					WChar types_array[] = {0, SCC_TOWN_NAME, SCC_NUM};
-					StringParameters tmp_params(args_array, 3, types_array);
+					auto tmp_params = MakeParameters(STR_TOWN_NAME, st->town->index, st->index);
 					GetStringWithArgs(builder, string_id, tmp_params);
 				}
 				break;
diff --git a/src/strings_internal.h b/src/strings_internal.h
index 208f082a9d..a78c72f3a8 100644
--- a/src/strings_internal.h
+++ b/src/strings_internal.h
@@ -15,24 +15,23 @@
 
 class StringParameters {
 protected:
-	StringParameters *parent; ///< If not nullptr, this instance references data from this parent instance.
+	StringParameters *parent = nullptr; ///< If not nullptr, this instance references data from this parent instance.
 	uint64 *data;             ///< Array with the actual data.
 	WChar *type;              ///< Array with type information about the data. Can be nullptr when no type information is needed. See #StringControlCode.
 
 	WChar next_type = 0; ///< The type of the next data that is retrieved.
 	size_t offset = 0; ///< Current offset in the data/type arrays.
 
-public:
-	size_t num_param; ///< Length of the data array.
-
 	/** Create a new StringParameters instance. */
 	StringParameters(uint64 *data, size_t num_param, WChar *type) :
-		parent(nullptr),
 		data(data),
 		type(type),
 		num_param(num_param)
 	{ }
 
+public:
+	size_t num_param; ///< Length of the data array.
+
 	/**
 	 * Create a new StringParameters instance that can reference part of the data of
 	 * the given partent instance.
@@ -169,11 +168,13 @@ public:
  */
 class AllocatedStringParameters : public StringParameters {
 	std::vector<uint64_t> params; ///< The actual parameters
+	std::vector<WChar> types; ///< The actual types.
 
 public:
-	AllocatedStringParameters(size_t parameters = 0) : StringParameters(nullptr, parameters, nullptr), params(parameters)
+	AllocatedStringParameters(size_t parameters = 0) : StringParameters(nullptr, parameters, nullptr), params(parameters), types(parameters)
 	{
 		this->data = params.data();
+		this->type = types.data();
 	}
 };