Thunderfire Cannon

Operated Artillery:You can only shoot with a Thunderfire Cannon if it is being operated. At the start of any phase, each Techmarine Gunner model from your army can operate one friendly Thunderfire Cannon model within 3" of it. Until the end of that phase, whilst it is within 3" of that Thunderfire Cannon, that Techmarine Gunner is said to be operating that Thunderfire Cannon

Crewed Artillery:After this unit is set up on the battlefield for the first time, it is divided into two units, one containing the Thunderfire Cannon and the other the Techmarine Gunner. If at any point there are no friendly Techmarine Gunner units within 6" of a Thunderfire Cannon, that Thunderfire Cannon is destroyed.

When a Thunderfire Cannon is set up on the battlefield, the Techmarine Gunner is set up in unit coherency with it. From that point onwards, the Techmarine Gunner is treated as a separate unit.

At the end of your Movement phase this model can repair a single VEHICLE within 1". That model regains D3 lost wounds. A model can only be repaired once per turn.