Franklin Metro utility is a Metro utility tunnels and part of the Metro network. It's slightly irradiated, heavily so in some places, and partially water-filled. The Metro track tunnels are a section of the Blue Line east of Franklin Station.
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. Note: it's easy to become stuck in the dumpster that the player drops into.
This is a good area to loot for crafting items, there is a workbench in the first and last rooms of the loop. There is also one of almost every item needed for crafting items.
With Broken Steel installed and player's level is higher than 20, these ghouls will be replaced with feral ghoul reaver. At the extreme end, every single ghoul, bar one or two roamers, will either be glowing ones or feral ghoul reavers, and due to their proximity you may be attacked by a group as large as five at once, particularly in the heavily irradiated tunnel.
Five Stealth Boys (including the one mentioned at map point A, see below).
Two are directly to your left when you enter the area, in the doorless metal tool closets.
One is at map point A
Two are at the top of the map (where it loops around) on a shelf before you drop back down to the beginning.
There is a possible Stealth Boy in the hard difficulty safe that's within sight upon entrance from Falls Church/Mason Dst Metro.
Two pre-War books in the upstairs part of the first room, in a bit and slightly to the left of the entry/exit door and immediately to the right of the open dumpster with the empty oil drum (if you look above you, this is also where you will eventually drop through at the end of the tunnel loop).
Tumblers Today near the door to Falls Church/Mason Dst Metro. It's in the downstairs part of the first room to the right of the turret. The book is on top of an average locked mine box where you fight a lot of glowing ones.
Guns and Bullets, downstairs in the center of the second room (not the one with the turret) on a desk, along with missiles.