Severe duty Double "Whack 'Em" Wheel Chock Idling locomotives and tank cars can lock a wheel chock under their wheel due to excess vibration. The "Whack 'Em" chocks have reinforced steel handles that will not bend from hammer blows or extreme handle pressure. These cast steel chocks feature an exclusive replaceable rail-biting steel spurs for excellent gripping power and handles and legs are painted red to indicate they are for severe duty.