The Pitt Underground

The Pitt Underground includes a sewer that can be accessed in the steel yard, near a wrecked train entering an inaccessable metro tunnel. There are numerous trogs in the area, but none in the sewer. Inside the sewer, two trogs can be seen canibalizing some unfortunate person from behind some bars.

There's no truth behind the rumor that there are no trogs in the underground. There are about a dozen of them, give or take. Generally, they come in groups of 3 to 4, with the occasional individual popping up out of nowhere (possible spawning). There is one instance of a massive group (4-5) spawning in pursuit of you as you reach the bottom of a ramp.

You can go all the way through the underground, but I haven't found much in the way of useful items, other than an employee id card, but the Protectrons don't bother me, except to say "move along, please." As of this writing (3/28/2009), I have not found a way to open the folding doors in the floor of the room uptown, to the left of the entrance to Haven. You'd think that by now I'd have found a switch on one side or the other of the door, but no such luck. Hopefully someone will update this for us. edited by BOP 3/28/2009.

Apparently the doors in the floor between the Underground and Uptown can only be opened if you assist Werhner. In which case, the "broken terminal" becomes functional and allows the doors to open. During this point in the quest, you unleash the trogs onto Uptown/Haven much like you would unleash the feral ghouls upon Tenpenny tower. If you do not assist Werhner, there is no way to open these doors. 3/29/09 -Har

Others have found just by releasing the Trogs by turning off the power to the lights, and continuing along the same path you came in by, the doors up to uptown are found already open without any further imput from the player (360 version).