The Tesla Lab in Dead Rails is a location that can be found at the 50-60km range (some have found it around 20-25km as well) and it contains Nikola Tesla and a gun called the Electrocutioner. The building cannot be missed, with its red color, multiple windows, and a Tesla Coil structure on top. There’s some valuable loot here aside from the weapon including Gold and Silver Bar, Lightning Rod, and some junk that can be sold.
Dead Rails Tesla Lab
When you enter this location, you will see some scattered limbs in various rooms. Carefully explore the area and collect the parts.
Once you have everything, drag them onto the table. What you’re doing is assembling Nikola Tesla.
After this, go to the room with the machine and turn on the power. You can do so by interacting with the lever in the middle. Press and hold E and the wheel should start turning. Be alert, because zombies will appear now. Take them down with your rifle, holy water or any other weapon of choice. Make sure you have Snake Oil and Bandages in case you take damage. You can also bring a horse here if you’d like.
Wait for the process to be over and you should be able to find the Electrocutioner which is a gun that shoots out lightning and spawns with 20 charges of ammo. The Electrocutioner’s ammo can only be recharged in two ways. First, you can use a Lightning Rod to strike it with lightning during a lightning storm. Second, you can use a holy weapon—like a Crucifix or Holy Water—on the dead body of an enemy with the gun placed next to it. When hit by lightning, the weapon fully recharges to its original 20 charges (ammo).
After you’ve assembled Nikola Tesla, he will spawn when you reach 80,000m. Your goal is to start lowering the bridge after which this boss will appear anytime after the 4:00 minute timer starts. You can hide inside a building and keep shooting at the boss who will be right outside the door. There will be other enemy types as well so be careful.
When you defeat the Tesla boss, you receive a badge and you can complete your journey.