/** Can't build tunnels on water */

		ERR_TUNNEL_CANNOT_BUILD_ON_WATER,            // [STR_ERROR_CAN_T_BUILD_ON_WATER]

		/** The start tile must slope either North, South, West or East */

		ERR_TUNNEL_START_SITE_UNSUITABLE,            // [STR_ERROR_SITE_UNSUITABLE_FOR_TUNNEL]

		ERR_TUNNEL_ANOTHER_TUNNEL_IN_THE_WAY,        // [STR_ERROR_ANOTHER_TUNNEL_IN_THE_WAY]

		/** Unable to excavate land at the end to create the tunnel's exit */

		ERR_TUNNEL_END_SITE_UNSUITABLE,              // [STR_ERROR_UNABLE_TO_EXCAVATE_LAND]

	};