C.S.
My son does this too. He is an only child, but he's hit me with his "choo choo" before. The only suggestion I can make would be to give him only plush toys for the time being. I hope to god this is just a phase and they will grow out of it, but I don't want to have a scarred up face while he's learning not to hit or throw his toys either. I have been thinking about limiting my sons toys to plush and maybe only letting him play with his "choo choo" when supervised. I just don't think they comprehend yet how they are hurting when they hit or throw. Good luck.