Half-Life 2 Walkthrough - Chapter 3: Route Kanal - Riding the Underground Railroad
This section of the Half-Life 2 walkthrough covers the battles that occur from the first underground railroad station to the area before the barnacle puzzles. If you can't handle the Combine soldiers or are confused about the path for the underground railroad, then look inside for the quick fix.
The Underground Railroad
Go out the open door and then break the boards blocking the path to the right. Keep going and walk up to the big patch of boards up ahead. Start breaking the boards until the whole things gives out. The car gets caught on the structure up ahead. If you're crouched, then you will be fine. Watch the crow fly into the barnacle and run under it while it's busy eating its catch. Zig zag through the tunnels and realize that your next safe haven is under attack. Shoot the two soldiers through the sewer gate if you can.
There's a machine gun position around the corner. It will kill you quickly if you don't have cover, so be ready to run. Round the corner and move to the right to enter the open sewer pipe in front of the boxes. Turn and follow it to the station. Pick up the health, energy, and ammo to get ready for the next part. When you're ready, climb the ladder and surprise the gunner and the soldier. Your best bet is to run to the back wall and shoot the explosive barrel right next to them.
Press “E" to use the gun and shoot the explosive barrels on the platform to the right. This will create a bridge to the sewer system across from you. Wait a few seconds and use the machine gun to kill the bulk of the reinforcements, but be ready to run if you see an armored car approach. You can't hope to dent it and it will use those rockets to take you out pretty quick.
You need to run along the little cement pathway to the right and cross the lowered wooden platform to the area under the bridge. There are three barnacles. Just step around the tongues of the first two, then kill the third to clear the path. Go forward and another resistance member will stop to give you directions to the next station. Go into the next pipe and turn to the right. You can just ignore the soldiers up top if you move quickly. Drop into the water ahead and make a note of the locked gate over the sewer pipe.
Stay above the surface and wait for the explosive barrels to start rolling into the water. They'll throw a flaming one in at the end. As soon as you see the flaming barrel, duck below the water and wait for the explosions to end. Then look up and shoot the two combine. Go through the sewer grate that is now conveniently blown open. Walk outside into the canal ahead.
First Canal Battle
Two combine drop down to the left of your exit. Just shoot them with the pistol. Another drops down ahead of you toward the right. Shoot him. Then walk toward the bridge ahead. Combine flood the bridge, but it doesn't really matter. Shoot the barrels to blow up the bridge and take them all out at once. Walk under the bridge and watch your sides. One combine drops down on each side. Kill them both and look to the little gap in the sewer gate to the right. Climb in and push one of the barrels forward.