DON'T DO IT!
Why not? Remember: there's a real person driving that train. You're forcing the train driver to be your bus. He doesn't want to be in that position, even if he's not a pro-lifer. He doesn't want to be an instrument of your death. He just wants to drive his route, then leave for the day, get home, drink a beer, and go to bed. At best, you'll ruin his day. At worst, you'll give him PTSD for life. We're an ethical community. So if you catch the bus, you gotta do it ethically, without involving an unwilling participant. Find another method.
The only exception to the above is if a rail line runs in an open-cut trench, and the bus-catcher "accidentally" fell off an overpass onto the tracks. Then the driver can tell himself that person was already dead on the tracks by the time his train hit them. You're giving the driver plausible deniability, to himself, first and foremost. Hitting a dead body is merely disrespectful. Hitting a living person is akin to murder.