diff --git a/src/engine.cpp b/src/engine.cpp
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -882,7 +882,7 @@ void ClearEnginesHiddenFlagOfCompany(Com
  * @param text Unused.
  * @return The cost of this operation or an error.
  */
-CommandCost CmdSetVehicleVisibility(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
+CommandCost CmdSetVehicleVisibility(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const std::string &text)
 {
 	Engine *e = Engine::GetIfValid(GB(p2, 0, 31));
 	if (e == nullptr || _current_company >= MAX_COMPANIES) return CMD_ERROR;
@@ -906,7 +906,7 @@ CommandCost CmdSetVehicleVisibility(Tile
  * @param text unused
  * @return the cost of this operation or an error
  */
-CommandCost CmdWantEnginePreview(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
+CommandCost CmdWantEnginePreview(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const std::string &text)
 {
 	Engine *e = Engine::GetIfValid(p1);
 	if (e == nullptr || !(e->flags & ENGINE_EXCLUSIVE_PREVIEW) || e->preview_company != _current_company) return CMD_ERROR;
@@ -927,7 +927,7 @@ CommandCost CmdWantEnginePreview(TileInd
  * @param text unused
  * @return the cost of this operation or an error
  */
-CommandCost CmdEngineCtrl(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
+CommandCost CmdEngineCtrl(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const std::string &text)
 {
 	if (_current_company != OWNER_DEITY) return CMD_ERROR;
 	EngineID engine_id = (EngineID)p1;
@@ -1079,12 +1079,12 @@ static bool IsUniqueEngineName(const std
  * @param text the new name or an empty string when resetting to the default
  * @return the cost of this operation or an error
  */
-CommandCost CmdRenameEngine(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const char *text)
+CommandCost CmdRenameEngine(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32 p2, const std::string &text)
 {
 	Engine *e = Engine::GetIfValid(p1);
 	if (e == nullptr) return CMD_ERROR;
 
-	bool reset = StrEmpty(text);
+	bool reset = text.empty();
 
 	if (!reset) {
 		if (Utf8StringLength(text) >= MAX_LENGTH_ENGINE_NAME_CHARS) return CMD_ERROR;