The vertical component of the vibration that could not be eliminated because of the weight needed to balance the pistons is called hammering. This is destructive to both the locomotive and the roadbed. In some locomotives, this hammering can be so intense that at speed, the drivers alternately jump from the rail head, then slam down hard on the rails as the wheels complete their rotation. Unfortunately, hammering is inherent to conventional two-cylinder piston-driven steam locomotives and that is one of the several reasons they have been retired from service.