Index: ps/trunk/binaries/data/mods/public/simulation/components/Promotion.js
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/components/Promotion.js
+++ ps/trunk/binaries/data/mods/public/simulation/components/Promotion.js
@@ -4,6 +4,11 @@
 	"<element name='Entity'>" +
 		"<text/>" +
 	"</element>" +
+	"<optional>" +
+		"<element name='TrickleRate' a:help='Trickle of XP gained each second.'>" +
+			"<ref name='nonNegativeDecimal'/>" +
+		"</element>" +
+	"</optional>" +
 	"<element name='RequiredXp'>" +
 		"<data type='positiveInteger'/>" +
 	"</element>";
@@ -11,6 +16,7 @@
 Promotion.prototype.Init = function()
 {
 	this.currentXp = 0;
+	this.ComputeTrickleRate();
 };
 
 Promotion.prototype.GetRequiredXp = function()
@@ -91,10 +97,44 @@
 	Engine.PostMessage(this.entity, MT_ExperienceChanged, {});
 };
 
+Promotion.prototype.ComputeTrickleRate = function()
+{
+	this.trickleRate = ApplyValueModificationsToEntity("Promotion/TrickleRate", +(this.template.TrickleRate || 0), this.entity);
+	this.CheckTrickleTimer();
+};
+
+Promotion.prototype.CheckTrickleTimer = function()
+{
+	if (!this.trickleRate)
+	{
+		if (this.trickleTimer)
+		{
+			let cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
+			cmpTimer.CancelTimer(this.trickleTimer);
+			delete this.trickleTimer;
+		}
+		return;
+	}
+
+	if (this.trickleTimer)
+		return;
+
+	let cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
+	this.trickleTimer = cmpTimer.SetInterval(this.entity, IID_Promotion, "TrickleTick", 1000, 1000, null);
+};
+
+Promotion.prototype.TrickleTick = function()
+{
+	this.IncreaseXp(this.trickleRate);
+};
+
 Promotion.prototype.OnValueModification = function(msg)
 {
-	if (msg.component == "Promotion")
-		this.IncreaseXp(0);
+	if (msg.component != "Promotion")
+		return;
+
+	this.ComputeTrickleRate();
+	this.IncreaseXp(0);
 };
 
 Engine.RegisterComponentType(IID_Promotion, "Promotion", Promotion);
Index: ps/trunk/binaries/data/mods/public/simulation/data/auras/structures/barracks_xp_trickle.json
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/data/auras/structures/barracks_xp_trickle.json
+++ ps/trunk/binaries/data/mods/public/simulation/data/auras/structures/barracks_xp_trickle.json
@@ -0,0 +1,9 @@
+{
+	"type": "garrisonedUnits",
+	"affects": ["Unit"],
+	"modifications": [
+		{ "value": "Promotion/TrickleRate", "add": 1 }
+	],
+	"auraName": "Rigorous Training",
+	"auraDescription": "Units gain experience while garrisoned in barracks."
+}
Index: ps/trunk/binaries/data/mods/public/simulation/templates/template_structure_military_barracks.xml
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/templates/template_structure_military_barracks.xml
+++ ps/trunk/binaries/data/mods/public/simulation/templates/template_structure_military_barracks.xml
@@ -1,5 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Entity parent="template_structure_military">
+  <Auras datatype="tokens">
+    structures/barracks_xp_trickle
+  </Auras>
   <Cost>
     <BuildTime>150</BuildTime>
     <Resources>