Go to the upper level of the train car that held several enemy soldiers. Head to the far end, climb up, and walk across to the nearby beam. Cut a hole in the fence using the Laserkraftwerk, move through it, and pick up the Targeting Scope on the ground. Sneak past the Kampfhund in the car and keep moving. Go across to the next one and drop in. Cut through another fence and keep dropping down until you're on a broken section of a bridge. You'll find a couple of soldiers trying to dislodge a pinned robot. Throw Hand Grenade at them, then run over to pick up the weapon the robot drops. You'll be attacked by a second robot inside a train car on the left. Use your new gun to blast him, then recharge it using a nearby kit, located at the closest end of the wreckage. Try to make this weapon last for as long as you can, since its massive firepower can annihilate foes. You'll come to a right turn as you progress. You'll come face-to-face with a big, angry, armored soldier as soon as you enter the building. Use whatever juice is left in the robot gun on him, then switch to some high-powered weaponry to finish him off. Once he's dealt with, pick up his gun, head up the stairs, and kill all the Nazis on the top level. Once they're taken care of, engage some drones, then drop down to the next area. Here, you should find a charge kit to power up your new favorite gun. Use the Laserkraftwerk to cut a hole in the ground, then pick your big gun back up and go down into the air ducts. You'll have a good firing position on an armored soldier and a platoon of light infantry. Wipe them out with the robot gun, then use the stairs to reach the bottom floor. Keep an eye on the upper catwalks, since soldiers are lurking up there. Clear out the next room, ditch the robot gun, and exit to the catwalk. Ignore the ladder on your left and go right. Run and jump across in order to trigger a cut scene.
Once you're back in control, jump into the turret while Fergus pilots the aircraft. Shoot all enemies on sight. Special priority should be given to the giant armored Kamphund before it drags the helicopter down. Keep firing until you run out of ammo, then hop down and finish them off with your personal arsenal.