A mechanism to assist in raising and lowering a hinged deck end section wherein a lifting force is applied to the deck end section by a counterweight mechanism. In the preferred embodiment, the counterweight mechanism operates in conjunction with a conventional, proven spring assist mechanism of the type that has been used in the past on trilevel railway cars. The counterweight mechanism preferably includes a counterweight that is slidable along a vertical track in a location that is readily accessible for visual inspection and maintenance. Nonmetallic wear pads are preferably employed in conjunction with a dry film lubricant to control friction between the counterweight and the track. The mechanism preferably provides a mechanical advantage so that the lifting force applied by the counterweight mechanism exceeds the weight of the counterweight. A roller chain, steel cable, or the like is preferably employed to connect the weight to the deck end section.