The Torka Cruiser is a very early Cardassian "heavy cruiser" design. The Torka sports a mix of compressor, phaser, and torpedo weaponry which, at the time, were top of the line hardware for the Cardassian Union. Pressed into service to serve the Cardassians during one of their major military expansion campaigns, the Torka Cruiser was adequate at combating most minor system's ships.
After only about twenty years the Torka was beginning to feel its age. Early confrontations with Federation cruisers proved that the Torka lacked the shield and weapons strength to be a valid combatant. Most of the Torkas were relegated to backwater system where they served in the role of system monitors, keeping watch over uninteresting systems within the Cardassian sphere of influence. As the Galor Cruiser became more and more widely used, however, the Torkas were slowly pulled out of service and mothballed at shipyards orbiting Cardassia Prime.
When the Klingons began attacking Cardassian planets before the Dominion War lit the galaxy afire, the Cardassians were forced to bring their Torka Cruisers out of mothballs. Many of these sturdy cruisers were then refitted into Tonga Blockade Cruisers.