i just bomb and run if you have to. When i do train run ups at stations i set myself up in the bushes next to the tracks and then run up and hit the train then run back to the bushes. I make sure cameras dont pick me up and that the driver and no one els sees me. I do maybe 3-4 trains and then just move up to the next station.
Mix it up, use your fists and your kicks to get out of shit.