A toy building set comprising a number of toy building elements and an overload-safe linear actuator having a center axis and with two spindle parts comprising a first spindle part with an internal thread arranged concentrically to the center axis, and a second spindle part with an external thread screwed into the internal thread on the first spindle part, and wherein the thread on the one spindle is at least twice as long as the thread on the second spindle part. One of the spindle parts being provided with a slot extending through the spindle part longitudinally of the thread configured on the spindle part and essentially along the entire thread, it is accomplished that it is easy to adjust the length of the actuator by pulling or pressing the two spindle parts together or away from each other.