It's coming right at us!!!!
Of course you want to know what it would feel like to lie down on a train track and watch a train speed over top of us as the ground shakes, the rails shimmy and sunlight comes strobing in between the vehicle's massive steel wheels. But—I can't stress this enough—do not attempt to get first hand experience of this. That's a great way to also experience premature death.
If you simply must indulge your curiosity, do it via this video created when someone placed his GoPro in the path of a coming locomotive: