The sealed train tunnel is an unmarked location in the Mojave Wasteland. It is located at the end of the railroad tracks, west-southwest of Ranger Station Charlie, and is inhabited by Vipers. The nearest fast travel location is Harper's shack, located in the northwestern hills above the train tunnel.
The location consists of an inaccessible train tunnel and a campfire in front of it. A group of five Vipers roam around the area. North of the campfire are several cacti, only one of which can be harvested for prickly pear fruit. Three more harvestable cacti are located a short way in east-southeastern direction from the tunnel.
Further east, near the unmarked road, a dead Bright follower is leaning against a rock. The hilltop billboard on the other side of the road is an ambush location. It usually houses three more Vipers, which may be replaced by legionary assassins or NCR Ranger hit squads, depending on the Courier's reputation.