Metro ticket

Metro tickets are miscellaneous items in Fallout 3.

Characteristics
Metro tickets are requested at any metro station in the Capital Wasteland that still has active protectrons. Having a ticket can prevent one of these robots from becoming hostile. These protectrons are inactive by default, but can be activated if the player can hack a nearby terminal as they then come out of their capsule and search the area for hostiles and passengers (you if you have a ticket).

Locations
Metro tickets aren't found in abundance around the wasteland except in Metro stations, but if the add-on Broken Steel, as many as 50 tickets can be found scattered throughout the Olney Powerworks. In one section of the Powerworks, there is a desk with a stack of Metro tickets that are assembled in a traditional triangular card stack.

Some feral ghouls in the Metro tunnels carry tickets, implying that they were passengers before radiation transformed them into ghouls.

Bugs

 * Sometimes when the protectron scans the player for a ticket, it will not detect the ticket(s) in the player's inventory and will become hostile.