Index: ps/trunk/binaries/data/mods/public/simulation/ai/petra/attackPlan.js
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/ai/petra/attackPlan.js
+++ ps/trunk/binaries/data/mods/public/simulation/ai/petra/attackPlan.js
@@ -368,7 +368,7 @@
 		return false;
 
 	let civ = gameState.getPlayerCiv();
-	let classes = [["Siege", "Melee"], ["Siege", "Ranged"], ["Elephant", "Melee"]];
+	const classes = [["Siege+Melee"], ["Siege+Ranged"], ["Elephant+Melee"]];
 	let hasTrainer = [false, false, false];
 	for (let ent of gameState.getOwnTrainingFacilities().values())
 	{
@@ -625,7 +625,7 @@
 	{
 		// find the actual queue we want
 		let queue = this.queue;
-		if (MatchesClassList(firstOrder[3].classes, ["Siege", "Elephant+Melee+Champion"]))
+		if (firstOrder[4] == "Siege")
 			queue = this.queueSiege;
 		else if (firstOrder[3].classes.indexOf("Hero") != -1)
 			queue = this.queueSiege;
Index: ps/trunk/binaries/data/mods/public/simulation/ai/petra/headquarters.js
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/ai/petra/headquarters.js
+++ ps/trunk/binaries/data/mods/public/simulation/ai/petra/headquarters.js
@@ -721,10 +721,9 @@
 	let units;
 	if (classes.indexOf("Hero") != -1)
 		units = gameState.findTrainableUnits(classes, []);
-	else if (classes.indexOf("Siege") != -1)	// We do not want siege tower as AI does not know how to use it
-		units = gameState.findTrainableUnits(classes, ["SiegeTower"]);
-	else						// We do not want hero when not explicitely specified
-		units = gameState.findTrainableUnits(classes, ["Hero"]);
+	// We do not want siege tower as AI does not know how to use it nor hero when not explicitely specified.
+	else
+		units = gameState.findTrainableUnits(classes, ["Hero", "SiegeTower"]);
 
 	if (!units.length)
 		return undefined;