diff --git a/src/newgrf.cpp b/src/newgrf.cpp
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -8372,13 +8372,13 @@ static bool ChangeGRFParamValueNames(Byt
 		byte langid = buf->ReadByte();
 		const char *name_string = buf->ReadString();
 
-		std::pair<uint32, GRFTextList> *val_name = _cur_parameter->value_names.Find(id);
-		if (val_name != _cur_parameter->value_names.End()) {
+		auto val_name = _cur_parameter->value_names.find(id);
+		if (val_name != _cur_parameter->value_names.end()) {
 			AddGRFTextToList(val_name->second, langid, _cur.grfconfig->ident.grfid, false, name_string);
 		} else {
 			GRFTextList list;
 			AddGRFTextToList(list, langid, _cur.grfconfig->ident.grfid, false, name_string);
-			_cur_parameter->value_names.Insert(id, list);
+			_cur_parameter->value_names[id] = list;
 		}
 
 		type = buf->ReadByte();