diff --git a/OpenRA.Mods.Common/OpenRA.Mods.Common.csproj b/OpenRA.Mods.Common/OpenRA.Mods.Common.csproj
index 5a1e2c55d7..12f913b9e7 100644
--- a/OpenRA.Mods.Common/OpenRA.Mods.Common.csproj
+++ b/OpenRA.Mods.Common/OpenRA.Mods.Common.csproj
@@ -776,6 +776,7 @@
     <Compile Include="Traits\World\CliffBackImpassabilityLayer.cs" />
     <Compile Include="Traits\Upgrades\GrantCondition.cs" />
     <Compile Include="Traits\Upgrades\ExternalConditions.cs" />
+    <Compile Include="Traits\Upgrades\StackedCondition.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <Target Name="AfterBuild">
diff --git a/OpenRA.Mods.Common/Traits/Upgrades/StackedCondition.cs b/OpenRA.Mods.Common/Traits/Upgrades/StackedCondition.cs
new file mode 100644
index 0000000000..3d0e6d2c69
--- /dev/null
+++ b/OpenRA.Mods.Common/Traits/Upgrades/StackedCondition.cs
@@ -0,0 +1,32 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2016 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Traits
+{
+	[Desc("Grant additional conditions when a specified condition has been granted multiple times.")]
+	public class StackedConditionInfo : TraitInfo<StackedCondition>
+	{
+		[FieldLoader.Require]
+		[UpgradeUsedReference]
+		[Desc("Condition to monitor.")]
+		public readonly string Condition = null;
+
+		[FieldLoader.Require]
+		[UpgradeGrantedReference]
+		[Desc("Conditions to grant when the monitored condition is granted multiple times.",
+			"The first entry is activated at 2x grants, second entry at 3x grants, and so on.")]
+		public readonly string[] StackedConditions = { };
+	}
+
+	public class StackedCondition { }
+}
diff --git a/OpenRA.Mods.Common/Traits/Upgrades/UpgradeManager.cs b/OpenRA.Mods.Common/Traits/Upgrades/UpgradeManager.cs
index 29ff0cc0ef..4c49bbbfc8 100644
--- a/OpenRA.Mods.Common/Traits/Upgrades/UpgradeManager.cs
+++ b/OpenRA.Mods.Common/Traits/Upgrades/UpgradeManager.cs
@@ -31,7 +31,6 @@ namespace OpenRA.Mods.Common.Traits
 	{
 		/// <summary>Value used to represent an invalid token.</summary>
 		public static readonly int InvalidConditionToken = -1;
-		string[] externalConditions = { };
 
 		class ConditionTimer
 		{
@@ -64,6 +63,15 @@ namespace OpenRA.Mods.Common.Traits
 		/// <summary>Each granted condition receives a unique token that is used when revoking.</summary>
 		Dictionary<int, string> tokens = new Dictionary<int, string>();
 
+		/// <summary>Set of whitelisted externally grantable conditions cached from ExternalConditions traits.</summary>
+		string[] externalConditions = { };
+
+		/// <summary>Set of conditions that are monitored for stacked bonuses, and the bonus conditions that they grant.</summary>
+		readonly Dictionary<string, string[]> stackedConditions = new Dictionary<string, string[]>();
+
+		/// <summary>Tokens granted by the stacked condition bonuses defined in stackedConditions.</summary>
+		readonly Dictionary<string, Stack<int>> stackedTokens = new Dictionary<string, Stack<int>>();
+
 		int nextToken = 1;
 
 		/// <summary>Temporary shim between the old and new upgrade/condition grant and revoke methods.</summary>
@@ -109,15 +117,21 @@ namespace OpenRA.Mods.Common.Traits
 				conditionCache[kv.Value] = conditionState.Tokens.Count > 0;
 			}
 
-			// Update all traits with their initial condition state
-			foreach (var consumer in allConsumers)
-				consumer.ConditionsChanged(self, readOnlyConditionCache);
-
 			// Build external condition whitelist
 			externalConditions = self.Info.TraitInfos<ExternalConditionsInfo>()
 				.SelectMany(t => t.Conditions)
 				.Distinct()
 				.ToArray();
+
+			foreach (var sc in self.Info.TraitInfos<StackedConditionInfo>())
+			{
+				stackedConditions[sc.Condition] = sc.StackedConditions;
+				stackedTokens[sc.Condition] = new Stack<int>();
+			}
+
+			// Update all traits with their initial condition state
+			foreach (var consumer in allConsumers)
+				consumer.ConditionsChanged(self, readOnlyConditionCache);
 		}
 
 		void UpdateConditionState(Actor self, string condition, int token, bool isRevoke)
@@ -135,6 +149,18 @@ namespace OpenRA.Mods.Common.Traits
 
 			foreach (var t in conditionState.Consumers)
 				t.ConditionsChanged(self, readOnlyConditionCache);
+
+			string[] sc;
+			if (stackedConditions.TryGetValue(condition, out sc))
+			{
+				var target = (conditionState.Tokens.Count - 1).Clamp(0, sc.Length);
+				var st = stackedTokens[condition];
+				for (var i = st.Count; i < target; i++)
+					st.Push(GrantCondition(self, sc[i]));
+
+				for (var i = st.Count; i > target; i--)
+					RevokeCondition(self, st.Pop());
+			}
 		}
 
 		/// <summary>Grants a specified condition.</summary>
@@ -193,7 +219,14 @@ namespace OpenRA.Mods.Common.Traits
 			if (state == null)
 				throw new InvalidOperationException("AcceptsExternalCondition cannot be queried before the actor has been fully created.");
 
-			return externalConditions.Contains(condition) && !conditionCache[condition];
+			if (!externalConditions.Contains(condition))
+				return false;
+
+			string[] sc;
+			if (stackedConditions.TryGetValue(condition, out sc))
+				return stackedTokens[condition].Count < sc.Length;
+
+			return !conditionCache[condition];
 		}
 
 		/// <summary>Returns whether the specified token is valid for RevokeCondition</summary>