Railgun turrets are a type of defense ordinance developed by the Terran Dominion.
Railgun turrets were in used by the time of the Defenders of Man insurgency. Nova Terra was able to outfit her ravens with experimental magnetic weaponry that allowed them to deploy railgun turrets instead of standard auto-turrets.
Railgun turrets deal 30 damage in a line when firing, but fire considerably slower than normal auto-turrets and cannot attack air units. This makes them effective against small numbers of small ground units.
Ravens can upgrade their auto-turrets to railgun turrets by equipping the Magrail Munitions upgrade.