--- a/src/ai/api/ai_cargo.hpp	Wed Jun 04 22:34:45 2008 +0000
+++ b/src/ai/api/ai_cargo.hpp	Wed Jun 04 22:57:17 2008 +0000
@@ -31,6 +31,18 @@
 	};
 
 	/**
+	 * The effects a cargo can have on a town.
+	 */
+	enum TownEffect {
+		TE_NONE       = 0, ///< This cargo has no effect on a town
+		TE_PASSENGERS = 1, ///< This cargo supplies passengers to a town
+		TE_MAIL       = 2, ///< This cargo supplies mail to a town
+		TE_GOODS      = 3, ///< This cargo supplies goods to a town
+		TE_WATER      = 4, ///< This cargo supplies water to a town
+		TE_FOOD       = 5, ///< This cargo supplies food to a town
+	};
+
+	/**
 	 * Checks whether the given cargo type is valid.
 	 * @param cargo_type The cargo to check.
 	 * @return True if and only if the cargo type is valid.
@@ -62,6 +74,13 @@
 	static bool HasCargoClass(CargoID cargo_type, CargoClass cargo_class);
 
 	/**
+	 * Get the effect this cargo has on a town.
+	 * @param cargo_type The cargo to check on.
+	 * @return The effect this cargo has on a town, or TE_NONE if it has no effect.
+	 */
+	static TownEffect GetTownEffect(CargoID cargo_type);
+
+	/**
 	 * Get the income for transporting a piece of cargo over the
 	 *   given distance within the specified time.
 	 * @param cargo_type The cargo to transport.