It is a very good picture Meatpie. It would be a quick death if you can make yourself do it. I feel sorry for the conductor of the train. I'm sure it was very traumatic for him to know his train took a life. Otherwise, the kid is very cute, probably in his teens. His head might look good mounted and hung over the fireplace.
Initially I thought he may have been drunk but come to think about it the way the head was severed hints that it was deliberate act by a fully conscious person. I wonder what he felt, we will never know.
My guess is horrific but is based on medical research. There is evidence that beheading victims remain conscious for a few seconds shortly after the body is severed and they can hear and think.
What if he thought, "That's it my body is gone, I am gonna die now."