Abstract: A rail car is adjustable in length to accommodate the mounting thereon of cargo containers of various lengths and widths, such as the presently employed 20 foot, 40 foot, 45 foot and 48 foot lengths and 96 and 102 inch widths. Length adjustment is effected either by forming the rail car frame in two telescopic end sections, or by providing an extensible coupling tongue on one or both ends of the rail car frame. The rail car also may incorporate a collapsible fifth wheel connector for the king pin of a cargo container trailer chassis to accommodate transport of a trailer-mounted cargo container. The rail car also includes structure by which it may be manipulated by external lifting equipment to stack a plurality of the rail cars one atop another, either for stationary storage in a rail yard or for transport in a train to another location.