modification to windows 10 creator 3d example train

I basically added a connector on the back of the train caboose, so the train can be as long as you want. please click the "I made one" button if you do print any of the files. also, if you do make this, please tell me what print settings you used, since I don't own a 3d printer. also, what else should I make? tell me in the comments (nothing too complex, because I am new to cad)