Trains have a set path and unlike cars their has been very few accidents. Boats are also very safe but limited to where they can go. I agree with planes being safe, But there is lots of ways they can crash. I can't think of any ways of travel efficient that would be better.
I think boats and planes are equal in safety because a boat can sink but if the crue members watch out it's a lower chance of happening. Also many planes crash to so i don't believe planes are the safer way to travel but that might just be me so yeah.