- "I've confirmed a gun train on their side. One hit with that thing and we're toast! Requesting air support!"
- ― Ed Alverez
Heavy artillery units, also known as guntrains, are railway-based vehicles designed for long-range attacks.
Heavy artillery units have made sporadic appearances in the series, starting with Ace Combat 6: Fires of Liberation. They're especially notable for being able to take massive amounts of damage.
The Estovakian Army deployed heavy artillery during the Siege of Silvat. Their objective was the settlement at the rear and the unit commander ordered them not to stop until "every one of them is dead." 
The Gavial Tank Battalion and Yellow Jacket helicopter unit defended Silvat from the guntrains. Once Garuda Team and multiple other reinforcements arrived, Emmerian forces succeeded in destroying the heavy artillery. The commander of Gavial and Bird Eater of Yellow Jacket were quick to commend the team effort it took to destroy them.
- In Infinity, when attacking the heavy artillery with LASMs, a glitch occurs when the missile attacks like it would against an enemy ship (skimming at low altitude, as opposed to attacking from an angle). If the heavy artillery in question is covered by buildings, this can make it harder to land a hit.
- Also, sometimes when one is destroyed, Sky-Eye will say "Target sunk."