Go to the stairway area in which you access the train station (across from Friendly Fire). To get onto the staircase past the barrier, do the glitch on the ground with any car to get past the barrier in the grassy area (where all the rocks are found). Once inside, wait for enemy gang to drive by on the road. Shoot their car once so they must drive past the barrier up to you. Then, kill the enemies, take the car, and drive it around to the front right side of the staircase where the corner sticks out. Make sure not to drive down or fall down the lower level where the benches are, as you will get stuck there unless you kill yourself. Angle your car sideways up on the hill so the vehicle is exactly perpendicular to it (the area between the staircase and the bridge). Jump on top of your car and keep jumping until you make it up. Sometimes if you are lucky you will teleport instantly on the staircase the moment you leave your car. You must position the car perfectly. You can now make your way up, see the people, and wait for the train. However, the barrier will still be on either of the sides. You will not have much of an area to explore.