As an end user of the fert., I can shed some light on the weight issue.... Basically, a pallet of fert is made up of 40 x 50kg bags, which equals 2 ton. The weight of the bags or loaded pallet hasn't changed over the years, except for a slight variation after the change from imperial to metric measurements... With the beams in the two centre compartments, a fully loaded wagon would hold 20 pallets, which was 40 ton....... However, in later years, a lot of the fert comes in large bulk bags. A pallet carries four of these large bags. Some bags hold 500kg, which means a pallet with four of these bags still weighs 2 ton, and didn't alter the fully loaded wagon weight. But...some of the bags hold 600kg of fert. So, a pallet of four would weigh 2.4 ton. and a wagon fully loaded with 20 of these pallets would be loaded to 48 ton.....