Kiritsugu is here to face a character who is really a glimpse of what he could have been. Both of them started out as assassins, but Train is really the only one who changed into a hero and stayed that way. Even as an assassin Train always kept his morals. Train is the better gunfighter and this should be reasonably easy for him. Train wins.
Update 8 7 2020 Kiritsugu has his Saber at the ready. Kiritsugu wins.