Half-Life 2 Walkthrough -> A Great Day
We proceed to Dr. Kleiner's lab. There, he'll say he's finished his teleport and will immediately send you and Alex to his old friend Eli's lab (Black Mesa East):
The Good Old Suit
Here, Barney will offer you the chance to change into the good old suit. When the door leading to the suit opens, a "Headcrab" named Lamar, tamed by Dr. Kleiner, will appear (jumping down from above). (By the way, Barney, even though Lamar's stinger has been removed, is terrified of him.)
Proceed to the room with the teleporter, which Kleiner will open using the panel behind the photo of scientists from the old Black Mesa. Contact Alyx's father, Dr. Eli. Alyx goes through the teleporter. Stand at the panel to the right of the teleporter, where three cables are plugged in. When one of them falls off, plug it back in:
On command, we flip the horizontal switch nearby. Alyx teleports. Then, for a second, the power in the lab goes out, and Kleiner asks Eli, "Did it work?" He replies, "See for yourself." Then Alex appears on the screen, shouting, "Hey, Doc!" and they all decide to teleport Gordon right away.
Failed transfer
We enter the teleporter, and just as we're about to be sent to Eli's lab, Lamar jumps on the teleporter and ruins everything:
The teleporter starts glitching, sending us to various locations—Brin's office in the Citadel, the desert, the sea, the lab—and eventually we find ourselves outside the window of Kleiner's lab. The doctor tells us to run. We climb down from the balcony and run.
The journey begins
We reach the railroad. Barney comes up to the platform and tells us to make our way to Dr. Eli ourselves. Then he throws down the oldest and, in my opinion, best weapon—a crowbar:
We head to the railroad. When we get down to the train cars, we'll come under fire from two cops on the right. Ignoring them, we run in the other direction. There's an open train car there. We grab a crate from it and carry it out onto the platform.
Using it, we climb up the platform and onto the car's roof. Jumping onto the tracks, we run to another open train car, through which we climb onto its roof. There, we run along the train car roofs and jump over the fence to the passage. We knock the lock off the door and go into the basement...
Through the sewers (part 1): Half-life 2 walkthrough
Source: GamesLife.ru