Abstract: A container, which is typically rectangular, includes a bottom and an upwardly extending sidewall. Upper and lower support surfaces, preferably adjacent the sidewall, allow the containers to be stacked. The container has an interlocking member for laterally coupling containers in one vertical column with containers in an adjacent vertical column. The interlocking member extends laterally from the outer surface of the sidewall. The interlocking member includes an upper portion extending a first distance above the upper support surface. The container includes a cavity extending upwardly from the bottom. The cavity is open at the bottom and is sized for insertion of the upper portion of an interlocking member therein. In so doing a container on one level becomes laterally interlocked with a container on a level either above or below it and to one side.

Abstract: A cart track assembly for use with a cart having steerable castor wheels includes a pair of parallel, spaced apart tracks mounted to a support surface. Each track includes a number of elongate main track segments and widened transition track segments coupling the main track segments. The main segments have parallel, upright sides defining a relatively narrow pathway between the sides. The widened segments preferably include sides which flare outwardly to define a widened transition area. The transition area is large enough to allow the castor wheels to pivot 180.degree. about their vertical pivot axis after the cart has reversed direction. This allows the castor wheels to roll smoothly along the track after the direction of the movement of the cart has been reversed.