You will have to approach a small lever which can be found to your left. Pull the lever and go back to a destroyed part of the balustrade. Check my screen, because that's where you must be standing. Wait for a train to show up here. It's going to take at least a few seconds, so you must be patient. You will also be given a new task.
New mission objective: Find a way into the inner perimeter through the train loading dock
It's very important that you don't try anything right away. You will have to wait for the LAST carriage to get closer to you. Perform a single jump and make sure that you've landed on it. You will also have to activate a reverse time feature right away. If you've done everything according to the plan, you will be allowed to go back to the loading dock (screen). Hide to your left and deactivate your suit. It's very important that you wait here for the suit to regenerate itself.
Enemy soldiers are occupying both sections of the loading dock, so you must have a lot of power at your disposal in order to avoid them. Use a slow-motion feature and start running forward. After that, you will have to use the stairs (screen). Hide somewhere to your left. It's very important that you don't stay in the open. Save your game.
Start off by securing the area around you. I would recommend choosing more powerful weapons here, especially since you'll be going against large groups. Hide behind one of the containers and eliminate enemy soldiers from there. I would recommend using a Surge Gun here, because one successful shot is more than enough to kill every soldier. You should also be aiming at explosive barrels and gas canisters (screen). Try securing both platforms of the loading dock. Once this is done, look around for valuable crates.
Now you will have to solve a simple riddle. Start off by going towards a small elevator (screen). This object should automatically move you to one of the upper balconies. Now you must find a control panel. Save your game once you're standing next to it.
Pull the lever and activate slow-motion at the same time. Jump down to the ground and start running forward. You will have to reach a stack of crates (screen). Use them to get on top of a large container. Deactivate slow-motion and wait for a large platform to get here. Perform a single jump, so you'll be able to land on it. Wait for the platform to reach your new destination. Thankfully, you won't have to reverse the time here.