side-tipping wagons have hydraulic, pneumatic or electric tipping equipment, that enables the wagon body to be lifted on one side. depending on the design, they may be tipped to both sides or just one side only. in order to prevent wagons from falling over during the tipping operation, some are equipped with track pinch bars with which they can be securely anchored to the trackbed. these wagons are often seen in unit trains being used to remove excavated material from major construction sites.