$***$I need help in understanding how to get the correct answer for this problem. The correct answer is at the bottom of the attached image$***$

Figure $($a$)$ below shows the manner in which a train wheel rests on the track. If the train travels at a constant speed of V$\_$C $=86$ mph and does not slip on the track, determine the x$-$component $($positive to the right$)$ of the velocity of point A in in$./$sec $($ A lies on the vertical line through the center C as shown in figure $($b$).$