Railsigns are a low-tech communications system invented and utilized by the Railroad in their shadow war against the Institute for the liberation of synthkind. They appear in Fallout 4 by association with the Railroad faction.

Background

Towards the turn of the 2280s, as the Railroad went through another identity shift with the resignation of Pinky Thompson as leader and Desdemona taking command of all Commonwealth operations thereafter, they welcomed Thomas Weatherby, going by the name "Tinker Tom," into their inner ranks after an attack by Institute forces destroyed his family's home. Weatherby's engineering ingenuity spearheaded the Railroad's rearmament and spurred an overhaul of their fundamentals including operational security and counterintelligence. One of these reforms included the railsign system as an amendment to their previous dead drop network, allowing agents to covertly mark field supply caches, hidden safehouses, and dead drop locations, as well as indicate the presence of allies or potential dangers without the need to use any sort of technology that might tip off agents of the Institute.^[1]

Symbols

Each marking consists of an "asterisk" of six or eight white lines, at the center of which is a special symbol, as follows:

Symbol	Name	Meaning
Plus: +	Ally	An ally is present nearby.
Square: ⬜	Cache	A supply cache can be found nearby.
Cross: X	Danger	A danger is present nearby or the area you are in is boobytrapped.
Arrow: ➔	Pointer	Shows the direction to something important.
House: 🏠	Safehouse	A Railroad safehouse is nearby.
Teardrop: 💧	Dead drop	A Railroad dead drop is nearby.

Locations

• A chalkboard found in the Railroad HQ beneath the Old North Church displays the six types of railsign and what each one means.
• Railsigns appear as a story element in the faction quest Tradecraft, where they are pointed out to the Sole Survivor by Deacon as a means to indicate the presence of ally Ricky Dalton who is referred to as "The Tourist."
• One can also find other railsigns across the Commonwealth, albeit rarely. Most are found at locations related to the Railroad faction, such as safehouses, dead drops, and around the Switchboard, typically close to a location's entrance.

Behind the scenes

• The concept of railsigns is similar to the shadowmarks utilized by the Thieves Guild from Bethesda's other work, The Elder Scrolls V: Skyrim, in that both are a low-tech system of glyphs used by underground societies to designate certain places and things to other members of their group.
  • They also bear a similarity to the real life hobo code - symbols allegedly used by the homeless and vagrants to let others know about various things related to their lifestyle, such are safe places to camp or places to get food.

References