Dreadnoughts exist to engage other capital ships and installations such as POS towers and modules, sovereignty structures, and stations. They do so through seige modules which significantly increase damage output at the expense of turret tracking and the ability to be remotely repaired as long as the seige module is active. In terms of training they are a direct extension of training for a T2 sniping battleship. They fit extra-large turrets and/or missile batteries with long and short range variants available. Seige modules render the dreadnought immune to jamming from EWAR.
Naglfar > Revelation > Moros > Phoenix