for the 'Wrong side of the tracks' mission, I drove ahead of the train, about half a mile (just before the bridge because any further Smoke says I lost the train... even though it's on tracks

) and I use my ak-47 to shoot 3 of the guys down, then smoke takes care of the rest, if he doesn't then I drive forward again and do what I did the first time.
'just business' has to be my favourite mission, along side of reuniting the famlies, fast pace action at it's best.