A convertible trailer system comprising: a convertible trailer having a segmented lower deck, a segmented upper deck mounted onto said lower deck by selectively actuable telescopic stanchions, said stanchions actuable by actuators so as to raise and lower said upper deck over said lower deck between a lowered position, an intermediately elevated position, and a fully elevated position, wherein in said fully elevated position said upper deck is elevated above said lower deck so as to allow loading of vehicles or freight onto said lower deck, wherein in said intermediately elevated position said upper deck is below said fully elevated position so as to be snugly adjacent uppermost extremities of said vehicles or freight on said lower deck, wherein in said lowered position said upper deck rests on a mid-section of said lower deck and on elevated wheel-wells of said lower deck, wherein said trailer includes a spaced apart longitudinally extending parallel pair of side rails and characterised in that said segmented lower deck includes a floating forward segment forward of said mid-section and independently actuable so as to be selectively raised and lowered relative to said pair of side rails, and wherein when in said fully lowered position said forward segment is lowered to a lower extremity between said pair of side rails substantially entirely below uppermost edges of said pair of side rails, and wherein when in said elevated position said forward segment is elevated so as to be co-planar with or above said uppermost edges of said side rails whereby freight is loadable laterally sideways onto said forward segment over said pair of side rails, wherein said segmented lower deck further includes a floating rear segment interposed between said floating forward segment and said mid-section of said lower deck, said floating rear segment independently actuable so as to be selectively raised and lowered and inclined relative to said pair of side rails and independently of said floating forward segment, and wherein, when in said fully lowered position, said floating rear segment is lowered to a lower extremity between said pair of side rails entirely below uppermost edges of said pair of side rails and substantially aligned with lower edges of said pair of side rails, and wherein, when in said elevated position, said floating rear segment is selectively positionable so as to be inclined or so as to be to horizontal and substantially co-planar with or above said uppermost edges of said side rails, whereby freight is loadable from a direction laterally oriented relative to the length of said trailer so as to load sideways onto said floating rear segment over said pair of side rails. a convertible trailer having a segmented lower deck, a segmented upper deck mounted onto said lower deck by selectively actuable telescopic stanchions, said stanchions actuable by actuators so as to raise and lower said upper deck over said lower deck between a lowered position, an intermediately elevated position, and a fully elevated position, wherein in said fully elevated position said upper deck is elevated above said lower deck so as to allow loading of vehicles or freight onto said lower deck, wherein in said intermediately elevated position said upper deck is below said fully elevated position so as to be snugly adjacent uppermost extremities of said vehicles or freight on said lower deck, wherein in said lowered position said upper deck rests on a mid-section of said lower deck and on elevated wheel-wells of said lower deck, wherein said trailer includes a spaced apart longitudinally extending parallel pair of side rails and characterised in that said segmented lower deck includes a floating forward segment forward of said mid-section and independently actuable so as to be selectively raised and lowered relative to said pair of side rails, and wherein when in said fully lowered position said forward segment is lowered to a lower extremity between said pair of side rails substantially entirely below uppermost edges of said pair of side rails, and wherein when in said elevated position said forward segment is elevated so as to be co-planar with or above said uppermost edges of said side rails whereby freight is loadable laterally sideways onto said forward segment over said pair of side rails, wherein said segmented lower deck further includes a floating rear segment interposed between said floating forward segment and said mid-section of said lower deck, said floating rear segment independently actuable so as to be selectively raised and lowered and inclined relative to said pair of side rails and independently of said floating forward segment, and wherein, when in said fully lowered position, said floating rear segment is lowered to a lower extremity between said pair of side rails entirely below uppermost edges of said pair of side rails and substantially aligned with lower edges of said pair of side rails, and wherein, when in said elevated position, said floating rear segment is selectively positionable so as to be inclined or so as to be to horizontal and substantially co-planar with or above said uppermost edges of said side rails, whereby freight is loadable from a direction laterally oriented relative to the length of said trailer so as to load sideways onto said floating rear segment over said pair of side rails.