The problem of the train method is not the traumatic effect per se, as I have said in this thread before, by commiting suicide you are risking traumatizing a lot of people. After you are gone there is no control over who will first see your corpse. It is the guilty the conductor will go through, as they will inevitably think they "could've stopped the train earlier" and performed any other security procedure better. Even if they are piloting a hard to control behemoth, and you jump in front of it as late as possible, they will still think they've killed someone, that's how humans (tend to) behave.
But even then, depending of how many people you have around in your life, you can also inflict guilty. Maybe you wish to (which is also selfish, even if it's as revenge), but if not, other people will still think they could've seen the signs earlier, stayed closer so they could've seen you planning the act, etc. I'd say to avoid suicide by train, thinking of the conductor, but it's not like this is the only method that will inflict pain onto others.