Abstract: A shipping rack which is convertible to a first rack length for snug lengthwise loading across the interior width of a semi-trailer and convertible to a second rack length for snug loading lengthwise across the interior width of a railroad boxcar. Pivotal rack extensions are provided on one end wall which will yield to potentially damaging forces and then self center. The rack extensions are held in a first position folded into the end wall to form the first rack length and are pivotal out of the end wall and are self positioning in a second position to form a second rack length.