The Railroad

 is an underground movement working to free sentient androids from their creators, the Institute. The Railroad also works to assist runaway human slaves.

Background
There is little available information about either the Railroad or the Institute, but the Lone Wanderer becomes involved in their conflict during the quest The Replicated Man in Rivet City, where a scientist named Dr. Zimmer requests aid in capturing a runaway android, and Railroad agent Victoria Watts pleads with the character to take pity on the android and fake its/his death.

The Railroad's methods for aiding in escape can be extreme, going so far as to find doctors to perform full facial reconstruction on escapees.

The Railroad is known to operate in the Capital Wasteland and at least as far north as the Commonwealth.

Dr. Zimmer, the android, and Ms. Watts give very logical and convincing arguments for their point of view, and the player must make an ethical choice based on the limited information he or she gains from each of them. There are multiple "good karma" solutions.

Victoria Watts, Manya Vargas, Father Clifford, Herbert Dashwood and Tulip are known members of the Railroad.

Appearances
The Railroad appears only in Fallout 3.

Behind the scenes
The Railroad is modeled after the "Underground Railroad.", an organization in the 1800's dedicated to saving black American slaves. Ironically, in the Fallout game world the railroad seems to be running in the opposite direction -- escaped androids flee south, out of the former state of Massachusetts.