carriage in open wagons pursuant to the General Conditions of Carriage or when it has been
expressly agreed and entered in the consignment note; subject to damage sustained by the goods
because of atmospheric influences, goods carried in intermodal transport units and in closed road vehicles carried on wagons shall not be considered as being carried in open wagons; if for the carriage of goods in open wagons, the consignor uses sheets, the carrier shall assume the same liability as falls to him for carriage in open wagons without sheeting, even in respect of goods which, according to the General Conditions of Carriage, are not carried in open wagons