Grand Theft Auto V : Sidetracked Walkthrough
Sidetracked is one of the Grand Theft Auto 5 missions. Drive toward the railroad yard and take out a couple of workers (on the both side of the control tower) from distance using sniper rifle.
You need to manipulate the rail controls and then switch to Michael. Grab the train engine using the skylift chopper and then line up gingerly from the back of the train. When the magnet key become visible, fly low and touch it. make your way to the trailer and reverse the process. Head back and grab a flatcar the same way. Head to the second trailer and drop off the car.