Add setting for whether non-leading train engines keep custom names

src/lang/extra/english.txt

@@ -201,6 +201,9 @@ STR_CONFIG_SETTING_THROUGH_LOAD_SPEED_LIMIT_HELPTEXT            :The maximum per
 STR_CONFIG_SETTING_RAIL_DEPOT_SPEED_LIMIT                       :Rail depot maximum speed: {STRING2}
 STR_CONFIG_SETTING_RAIL_DEPOT_SPEED_LIMIT_HELPTEXT              :The maximum permitted speed for trains when entering or exiting a rail depot
 
+STR_CONFIG_SETTING_NON_LEADING_ENGINES_KEEP_NAME                :Non-leading train engines keep custom names: {STRING2}
+STR_CONFIG_SETTING_NON_LEADING_ENGINES_KEEP_NAME_HELPTEXT       :Whether train engines with a custom name should keep their custom name when moved to a non-leading position in a train consist
+
 STR_CONFIG_SETTING_BACK_ONE_WAY_PBS_SAFE_WAITING                :Pathfind up to back of one-way path signals: {STRING2}
 STR_CONFIG_SETTING_BACK_ONE_WAY_PBS_SAFE_WAITING_HELPTEXT       :When enabled, the YAPF train pathfinder may pathfind up to the back of a one-way path signal.
 

src/settings_gui.cpp

@@ -2267,6 +2267,7 @@ static SettingsContainer &GetSettingsTree()
 			vehicles->Add(new SettingEntry("order.nonstop_only"));
 			vehicles->Add(new SettingEntry("vehicle.adjacent_crossings"));
 			vehicles->Add(new SettingEntry("vehicle.safer_crossings"));
+			vehicles->Add(new SettingEntry("vehicle.non_leading_engines_keep_name"));
 		}
 
 		SettingsPage *limitations = main->Add(new SettingsPage(STR_CONFIG_SETTING_LIMITATIONS));

src/settings_type.h

@@ -677,6 +677,7 @@ struct VehicleSettings {
 	bool   drive_through_train_depot;        ///< enable drive-through train depot emulation
 	uint16 through_load_speed_limit;         ///< maximum speed for through load
 	uint16 rail_depot_speed_limit;           ///< maximum speed entering/existing rail depots
+	bool   non_leading_engines_keep_name;    ///< allow engines moved to a non-leading position to retain their custom name
 };
 
 /** Settings related to the economy. */

src/table/settings/settings.ini

@@ -1503,6 +1503,14 @@ strval   = STR_JUST_VELOCITY
 cat      = SC_EXPERT
 patxname = ""vehicle.rail_depot_speed_limit""
 
+[SDT_BOOL]
+var      = vehicle.non_leading_engines_keep_name
+def      = false
+str      = STR_CONFIG_SETTING_NON_LEADING_ENGINES_KEEP_NAME
+strhelp  = STR_CONFIG_SETTING_NON_LEADING_ENGINES_KEEP_NAME_HELPTEXT
+cat      = SC_ADVANCED
+patxname = ""vehicle.non_leading_engines_keep_name""
+
 [SDT_BOOL]
 var      = pf.forbid_90_deg
 def      = true

src/train_cmd.cpp

@@ -2219,7 +2219,9 @@ CommandCost CmdMoveRailVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, u
 			/* Remove stuff not valid anymore for non-front engines. */
 			DeleteVehicleOrders(src);
 			src->unitnumber = 0;
-			src->name.clear();
+			if (!_settings_game.vehicle.non_leading_engines_keep_name) {
+				src->name.clear();
+			}
 			if (HasBit(src->vehicle_flags, VF_HAVE_SLOT)) {
 				TraceRestrictRemoveVehicleFromAllSlots(src->index);
 				ClrBit(src->vehicle_flags, VF_HAVE_SLOT);