Add setting to enable flipping direction of all train types in depot

src/lang/english.txt

@@ -1278,6 +1278,9 @@ STR_CONFIG_SETTING_CHUNNEL_HELPTEXT                             :When enabled, t
 STR_CONFIG_SETTING_NO_TRAIN_CRASH_OTHER_COMPANY                 :Trains from different companies may not crash into each other: {STRING2}
 STR_CONFIG_SETTING_NO_TRAIN_CRASH_OTHER_COMPANY_HELPTEXT        :This setting is primarily to prevent untrusted players deliberately causing crashes involving other companies' trains in multi-player rail infrastructure sharing games.
 
+STR_CONFIG_SETTING_FLIP_DIRECTION_ALL_TRAINS                    :All train vehicles may be direction flipped in depot: {STRING2}
+STR_CONFIG_SETTING_FLIP_DIRECTION_ALL_TRAINS_HELPTEXT           :Enable flipping the direction of all train vehicles in depots, even if it is not enabled by the NewGRF.
+
 STR_CONFIG_SETTING_NEVER_EXPIRE_AIRPORTS                        :Airports never expire: {STRING2}
 STR_CONFIG_SETTING_NEVER_EXPIRE_AIRPORTS_HELPTEXT               :Enabling this setting makes each airport type stay available forever after its introduction
 

src/settings_gui.cpp

@@ -1714,6 +1714,7 @@ static SettingsContainer &GetSettingsTree()
 			vehicles->Add(new SettingEntry("order.serviceathelipad"));
 			vehicles->Add(new SettingEntry("vehicle.adjacent_crossings"));
 			vehicles->Add(new SettingEntry("vehicle.safer_crossings"));
+			vehicles->Add(new SettingEntry("vehicle.flip_direction_all_trains"));
 		}
 
 		SettingsPage *limitations = main->Add(new SettingsPage(STR_CONFIG_SETTING_LIMITATIONS));

src/settings_type.h

@@ -541,6 +541,7 @@ struct VehicleSettings {
 	uint8  repair_cost;                      ///< cost of repairing vehicle
 	bool   ship_collision_avoidance;         ///< ships try to avoid colliding with each other
 	bool   no_train_crash_other_company;     ///< trains cannot crash with trains from other companies
+	bool   flip_direction_all_trains;        ///< enable flipping direction in depot for all train engine types
 };
 
 /** Settings related to the economy. */

src/table/settings.ini

@@ -1336,6 +1336,15 @@ strhelp  = STR_CONFIG_SETTING_NO_TRAIN_CRASH_OTHER_COMPANY_HELPTEXT
 extver   = SlXvFeatureTest(XSLFTO_AND, XSLFI_INFRA_SHARING)
 patxname = ""infra_sharing.vehicle.no_train_crash_other_company""
 
+[SDT_BOOL]
+base     = GameSettings
+var      = vehicle.flip_direction_all_trains
+def      = false
+str      = STR_CONFIG_SETTING_FLIP_DIRECTION_ALL_TRAINS
+strhelp  = STR_CONFIG_SETTING_FLIP_DIRECTION_ALL_TRAINS_HELPTEXT
+patxname = ""flip_direction_all_trains.vehicle.flip_direction_all_trains""
+cat      = SC_EXPERT
+
 ; station.join_stations
 [SDT_NULL]
 length   = 1

src/train_cmd.cpp

@@ -2254,7 +2254,7 @@ CommandCost CmdReverseTrainDirection(TileIndex tile, DoCommandFlag flags, uint32
 		if (v->IsMultiheaded() || HasBit(EngInfo(v->engine_type)->callback_mask, CBM_VEHICLE_ARTIC_ENGINE)) {
 			return_cmd_error(STR_ERROR_CAN_T_REVERSE_DIRECTION_RAIL_VEHICLE_MULTIPLE_UNITS);
 		}
-		if (!HasBit(EngInfo(v->engine_type)->misc_flags, EF_RAIL_FLIPS)) return CMD_ERROR;
+		if (!HasBit(EngInfo(v->engine_type)->misc_flags, EF_RAIL_FLIPS) && !_settings_game.vehicle.flip_direction_all_trains) return CMD_ERROR;
 
 		Train *front = v->First();
 		/* make sure the vehicle is stopped in the depot */