Fallout 4: The Nuclear Option - The Railroad

This guide will help you complete the Railroad Quest: The Nuclear Option in Fallout 4. This quest involves the final end-game events that occur when siding with the Railroad faction. Complete each objective of this quest to successfully execute the Railroad's plans.

The Nuclear Option concludes the Main Quest storyline and becomes available after siding with the Railroad faction and completing a series of their quests. This quest will vary depending on which faction players side with. If you would like to see how events play out for a different faction, you can find other faction quests on our Fallout 4 Walkthrough and Guide.

Talk to Desdemona

With the Brotherhood taken care of, it’s time to finish the plans that the Railroad has put into motion. Speak with Desdemona at the Railroad HQ to discuss how to proceed. Your job is to travel back to the Institute and find a way to teleport the rest of the crew into the building.

Talk to Z1-14

Use your Pip-boy Relay to fast travel to the Institute. Z1-14 can be found working in the Relay Control Room. To get there, push the call button on the center elevator in the main Institute hub, and ride the elevator to the top level. Z1-14 is working in a hallway just to the right of the control desk. Talk to Z1-14 to let him know that the plan is underway.

Kill Everyone in the Relay Control Room

You will need to clear out the control room before Z1-14 can access the control panel for the Relay. Proceed to kill all of the guards and scientists within the Relay Control Room, then wait for Z1-14 to get to work.

Talk to Desdemona

After a few moments, Z1-14 will teleport Desdemona and the rest of the team into the Institute through the Relay portal. Now that everyone has safely arrived in one piece, speak with Desdemona for further instructions.

Reach the Reactor

While Tinker Tom works to prepare the Relay for departure, you and Desdemona need to locate the Reactor. Desdemona hands you a Fusion Pulse Charge, which you will need to plant on the Reactor itself.

Head down the staircase east of the control desk, and enter the left door into Old Robotics. Prepare to battle a ton of Synths as you head toward the Reactor location. Hack the Advanced locked terminal and disable the turrets if you wish.

Continue through the various chambers until you reach the main Robotics laboratory on the lower level. Watch out for a Sentry Bot, Synths, and more turrets as you enter this lab. Eliminate the enemy threats, then pass through the east hallway to locate a hatch in the floor. Drop down the hatch, and continue through the passage until you reach a door to the Bioscience division.

Enter the Bioscience lab, and eliminate all hostiles in the room. Clear the lab, and continue through the door to reach the central Institute hub. Take out all of the Coursers and other Synth reinforcements that you encounter in this area.

Use Terminal to Override Institute Lockdown

• Optional: Issue Evacuation Order

After eliminating all of the hostiles in the center section of the Institute, Tinker Tom will chime in over the intercom to inform you that the Reactor is located in the Advanced Systems division. However, you’ll first need to override the lockdown before you can proceed, and overrides can only be initiated from the Director’s personal terminal.

Ride the center elevator down a level, then use another elevator to reach the floor where Father’s quarters are located. Head through the hallway and up the staircase into Father’s quarters. Either speak with Father to receive the terminal password, or simply hack the terminal instead. If you are able to convince Father to help your cause through the persuasive dialogue options, he will give you a code to disable most of the hostile Synths.

On the terminal menu screen, select the Master Security Lockdown Override. You can also optionally issue an evacuation order to clear out some Institute members if you wish.

Reach the Reactor

After issuing the override, go down the staircase just ahead of the computer terminal and return to the central hub area. Enter the doorway to the Advanced Systems division, and eliminate all hostiles in the next room.

Enter the door to the Reactor room. Continue up the long hallway to the west, and watch out for the series of laser turrets that line the left wall. Pass through the control room at the end of the hall, and take the left door leading down to the Reactor room. Eliminate the Synth hostiles, and walk up the scaffolding to reach the Reactor.

Plant Fusion Pulse Charge Inside Reactor

All you have to do now is plant the explosive device on the Reactor. Keep in mind that as soon as you open the door and step towards the Reactor, you will encounter a high amount of radiation, causing your Rads meter to rapidly increase. Have some radiation relief handy, such as RadAway or Rad-X, as well as Stimpaks or other healing items. You can also hack the terminal in front of the Reactor to prevent the radiation exposure altogether. Open the door and plant the Fusion Pulse Charge, then report back to Desdemona.

Talk to Desdemona

Once the charge is planted, speak to Desdemona, and she will instruct Tinker Tom to teleport both of you to safety.

Talk to Shaun

When you arrive in the Relay Control Room, you find an unexpected guest waiting for you. Speak with Shaun and decide what to do with him. You can either bring him along with you, or tell him to stay behind.

Talk to Tinker Tom

Speak with Tinker Tom and inform him of your decision regarding Shaun. When you’re ready to leave, tell Tinker Tom to fire up the Relay.

Step Into the Relay

Enter the Relay room just ahead of the control panel, and wait on the platform. In a few moments, Tinker Tom will teleport you and Desdemona safely to the rooftop of the Mass Fusion building.

Activate Detonator

When you arrive on the roof of Mass Fusion, there will be a detonator sitting on some crates just waiting to be pressed. Stand near the railing to ensure you have a clear view across the wasteland, and press the detonator button when ready. Nice work, agent!

Talk to Desdemona

Afterward, speak with Desdemona once more to discuss the future of the Railroad and the status of the Commonwealth. Although this concludes the Main Quest storyline, keep in mind that Radiant quests and some Miscellaneous quests are still available.

For more Fallout 4 quests and features, head over to USGamer’s Fallout 4 Walkthrough and Guide.