First of all, I'm not sure what the video has to do with what you're asking about (BTW, the video is a fake).
Second, if you stand/jump in front of the train, then of course the train is going to sweep you underneath it. The point is, though, that a train moving at high speed will deal a fatal injury to anyone it hits. I agree though, just envisioning it in my head, the train method seems a lot less surefire than it actually appears to be. I think you've just got to be able to trust in the laws of physics if you choose this method (or jumping, which is pretty much the same as standing in front of the train, except that instead of the train hitting you at high speed, you hit the ground at high speed instead - but the physical effect is more or less the same).