You can only start this quest once you have completed “The Molecular Level” main story quest.You also now be able to both enter the Railroad HQ and fast travel in and out of it. You will get to pick a nickname from a list of 7. Either way Desdemona will be impressed and offer you the chance to join the Railroad. You can play along with his exaggerations or not. When you arrive, Deacon will tell a grand story of how you assaulted the base.Once you are done speaking with Deacon, you can return to the Railroad Headquarters. Carrington’s prototype will be on a shelf in the same room. Inside there will be a dead Railroad agent. You will find a vault door locked by an inaccessible terminal that can only be unlocked through Deacon.
The Switchboard is overrun with Institute synths and turrets. There will be a set of T-45 power armor along the way. The entrance will be through a sewer near the Corvega Assembly Plant.
After some conversation, he will tell you about a place called the Switchboard.
There will be a few creatures along the way. You will then have to travel with him to meet the tourist. He will be standing in a secluded area dressed in a disguise.
How to Find and Join the Railroad? Road to Freedom Currently, they are led by a woman named Desdemona who has improved the Railroad’s operations significantly. The current iteration of the Railroad was preceded by another that was destroyed by the Institute. They have an intensive surveillance network throughout the Commonwealth. They use a system of dead drops and secret hideouts. Their base is hidden to the world, and their agents remain anonymous and use disguises. The Railroad works in secrecy out of necessity, as the Institute would destroy them if given the chance. Some in the Commonwealth view them as dangerous junkpiles that need to be eradicated, and some, like the Railroad, believe that they deserve the same rights as biological human beings.
(I will keep Institute spoilers to a minimum here). Synths are creations of The Institute, and the newer models are almost indistinguishable from humans.
They aim to free the enslaved and persecuted synths that live in the Commonwealth. The Railroad is similar to the underground railroad of American history.