Rail Guns are usable as a mounted weapon on the aircraft carrier U.S.S Arrowhead during the mission "Armada", where the player must use it to destroy two Atlas Corporation cargo ships.
In Multiplayer, it appears as an exclusive scorestreak for the map Atlas Gorge. Two controllable turrets are mounted high on the dam wall. The player can switch between the two turrets at any time during use. Each shot causes high explosive damage on impact and takes several seconds to reload. The turrets are also high enough to shoot down UAVs and Warbirds with a single shot.
The Railgun's HUD.
Using the Rail Guns in multiplayer.
Shooting the Rail Guns.
Call of Duty: Siege
The Rail Gun returns in Call of Duty: Siege as a defense card. It is able to be placed at the players base to defend against enemies. It is able to be obtained from the store or from a Supply Drop.