SRS, you have no idea what you are talking about. Some of your posts are helpful and informative, thank you. But Please Please Please don't post something just for the sake of posting.
Holding your arms straight (strate?) out and flapping your hands up and down, in most places, means you're imitating a bird.
"Holding your are" - what does than mean? Assuming you meant arm, holding your ARM straight above your head means release brakes.
Holding your arm out and rotating your hand counter clockwise (or clockwise for that matter) is going to be pretty hard for an engineer 25 cars away to see - especially at night!!!
Steam 371, you say you have learned the basics, so you already know stop, forward, back up, apply brakes, and release brakes, and a few others. And although a newbie, you no doubt already are laughing at how some folks THINK they know railroading just because they post things on forums. But as for those more exotic signals, your best bet would be to ask the guys you work with. Why? Because customized signals vary from place to place. There are signals for numbers (track 4, for example). Cut, kick, in the clear, tie on a brake, house track, - there are lots of them, and some that may be specific to your own railroad and no place else.
Take just one example - asking for slack when you want to make a cut. Some places you raise both hands above your head, gradually bringing your palms together. Some places you take both fists and butt them together in front of you. I've seen this indicated by both thumbs sticking up. And at night, or at great distance, you may have to just raise your lantern in the air, and make a very slow "back up" or "come ahead" as the case may be. And there are probably many more. What may be an every-day signal on your railroad may mean something else - or nothing at all - on mine.
If in doubt, give a "stop" and make sure your whole crew is on the same page before you continue. It's no different that a quarterback calling a time out if his line does not have a good understanding of the next play. And boxcars are even more dangerous than a 350 pound tackle!