Operation: You insert a piece of hard plastic into the gap on the left side of the railing in the picture to enlarge the gap, and then pry it open with a piece of hard sawdust (it can be made of other materials, as long as it is not easy to hurt the plastic skin of the liner). When you drive to a certain extent, the tracks can come out.

Note: be careful when operating, the plastic skin of the liner is very thin.