Are twin slot brackets strong enough to support a shelf layout?

Are twin slot brackets strong enough to support a shelf layout? twin slot shelving kit ShelvingDirect's Twin Slot Shelving is manufactured from superior quality steel to exacting tolerances to create a long-lasting and robust, space-saving twin turbos slot I've got a small length of test track and storagedisplay shelves setup on that exact type of shelving It's been on the wall for five years so

twin turbos slot Does anyone know if twin slot shelving is a standard ? I have some brackets from B&Q but they didn't have the tracks in stock Screwfix do but

twin spin slot bonus Rothley Twin Slot Shelving Kit 1600mm Upright 216mm Brackets White from Construction Supplies Buy Twin Slot Shelving at Free returns Everyday products, everyday prices Sign up to receive exclusive offers, vouchers and deals