diff --git a/src/command_type.h b/src/command_type.h
--- a/src/command_type.h
+++ b/src/command_type.h
@@ -22,7 +22,7 @@ struct GRFFile;
  * a possible error message/state together.
  */
 class CommandCost {
-	ExpensesType expense_type; ///< the type of expence as shown on the finances view
+public: ExpensesType expense_type; ///< the type of expence as shown on the finances view
 	Money cost;       ///< The cost of this action
 	StringID message; ///< Warning message for when success is unset
 	bool success;     ///< Whether the comment went fine up to this moment