Frcition-compensated runway

Note that friction acts in a direction opposite to the relative motion of the object.

That is, friction acts up the slope when the object is moving down the runway. This time, friction and mgsinθ acts in opposite direction. As the runway is friction-compensated, so the magnitude of the two forces are equal. They cancel out each other and the net force acting on the object is zero. By Newton's 1st law of motion, it will move down the runway with constant velocity.

But in your case, if friction and mgsinθ acts in the same direction, then the object must be moving up the slope, so that friction can act in a direction opposite to the relative motion of the object. In this case, a force should be applied to the object so it can move with constant velocity upward.

F = f + mgsinθ