The blue 4-car train stands on a complicated track system, depicted by the black lines. You are supposed to shunt the train into the position shown in gray. For this you can move the train back and forth. Click on the first or last car to define it to be the head of the train. This head is then marked by a red line. Then get moving by clicking near the middle of the rail the head will move to in the next step. But note that the train can not drive through itself, the head is not even supposed to touch the rest of the train. Reverse moving direction (redefine the head) by clicking on the last car. How many steps are necessary?