Franklin Metro Utility

 is a few Metro utility tunnels, part of the Metro track tunnels, and a cave system. It's slightly radiated, heavy in places, and partially waterfilled.

The tunnel loops back onto itself, and you can drop down a hole in the floor to reach the beginning after you've been through. Be warned that it's quite easy to become stuck in the dumpster that the player drops into.

This is an amazing area to loot if you're into creating items at workbenches. Not only is there a workbench at the end of the loop (before you drop down) but there is almost one of every item you'll need for your creations.

Inhabitants

 * A lot of Feral Ghouls and Glowing Ones.

Notable loot

 * Guns and Bullets on a desk, downstairs towards the radiated/waterfilled area (A).
 * A very useful Radiation Suit and a Mini Nuke at the end of the waterfilled tunnel (B).
 * Burnmaster in a heavily radiated end of the tunnel, in a freight car (C).
 * U.S. Army: 30 Handy Flamethrower Recipes in a bookshelf (D).
 * Tumblers Today near Falls Church/Mason Dst Metro, go downstairs there is a generator and a turret. The book is on top of an average locked mine box where you fight a lot of glowing ones.
 * Five to six Stealth Boys. Two directly to your left when you enter the area, and a third next to the Guns and Bullets book.  Two more are at the top of the map (where it loops around, on a shelf before you drop back down to the beginning.)