motion change as the pendulum is an arrangement to open and close an electrical pathway by actuating a switch which is provided with tensions of springs and an air actuated piston in an arrangement to effect the relationship of the pendulum and the forked bar to which the switch is secured which may supply electrical currents to the air handling apparatus which provide air pressure forces to braking cylinders causing resistance to the turning of the wheels and the surface provides the traction which effects the quality of reduction of momentum this induces the position of the pendulum that selects the mode of braking intermittent or conventional traction of the wheels affects the movement of the pendulums if the wheels hold the pendulums move forward the pendulum in relation to a forked bar provided with spring tensions and actuated by a piston propelled by air pressure allows a graduated application of the intermittent rapid on and off braking this extends to the rapid intermittent braking to a greater degree in resistance to motion as the air pressure is increased for example using low air pressure 10 15 lb the intermittent braking will allow the pendulum to move forward out of the intermittent range at a lesser pace of speed reduction to induce the conventional braking process than if the air pressures are increased requiring greater speed reduction before the conventional braking process is in effect the pendulum is provided with a safety switch which may be actuated by the end of a rod extending from the piston in the monitoring cylinder.