I've been wavering between methods because none is really easy and peaceful *sigh* but if I choose train my biggest fear would be staggering and falling before the train hits me (I wouldn't lie down on the tracks). So I'd kneel on the tracks with my body stiff and high up, arms spread a bit for balance, so the train will probably hit and crash my head, neck, shoulders... only. Which is enough to die. For me it must be a highspeed train: quicker and safer. Biggest risk is I think surviving with lost limps, so that must be evaded at all costs.