diff --git a/OpenRa.Game/OpenRa.Game.csproj b/OpenRa.Game/OpenRa.Game.csproj
index 9fc9b0bf7d..57c74ffc8b 100644
--- a/OpenRa.Game/OpenRa.Game.csproj
+++ b/OpenRa.Game/OpenRa.Game.csproj
@@ -109,6 +109,7 @@
     <Compile Include="Support\PerfHistory.cs" />
     <Compile Include="Traits\AcceptsOre.cs" />
     <Compile Include="Traits\Activities\Attack.cs" />
+    <Compile Include="Traits\Activities\CaptureBuilding.cs" />
     <Compile Include="Traits\Activities\Circle.cs" />
     <Compile Include="Traits\Activities\Demolish.cs" />
     <Compile Include="Traits\Activities\Fly.cs" />
@@ -179,6 +180,7 @@
     <Compile Include="Traits\BelowUnits.cs" />
     <Compile Include="Traits\Building.cs" />
     <Compile Include="Traits\C4Demolition.cs" />
+    <Compile Include="Traits\EngineerCapture.cs" />
     <Compile Include="Traits\Explodes.cs" />
     <Compile Include="Traits\ChronoshiftDeploy.cs" />
     <Compile Include="Traits\Fake.cs" />
diff --git a/OpenRa.Game/Traits/Activities/CaptureBuilding.cs b/OpenRa.Game/Traits/Activities/CaptureBuilding.cs
new file mode 100644
index 0000000000..4df1009190
--- /dev/null
+++ b/OpenRa.Game/Traits/Activities/CaptureBuilding.cs
@@ -0,0 +1,37 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace OpenRa.Game.Traits.Activities
+{
+	class CaptureBuilding : IActivity
+	{
+		Actor target;
+
+		public CaptureBuilding(Actor target) { this.target = target; }
+
+		public IActivity NextActivity { get; set; }
+
+		public IActivity Tick(Actor self)
+		{
+			if (target == null || target.IsDead) return NextActivity;
+			// todo: don't waste engineers on things that have been captured 
+			// between order issue time and the time we hit the building.
+
+			target.Health -= EngineerCapture.EngineerDamage;
+			if (target.Health <= 0)
+			{
+				target.Owner = self.Owner;
+				target.Health = EngineerCapture.EngineerDamage;
+			}
+
+			// the engineer is sacrificed.
+			Game.world.AddFrameEndTask(w => w.Remove(self));
+
+			return NextActivity;
+		}
+
+		public void Cancel(Actor self) { target = null; NextActivity = null; }
+	}
+}
diff --git a/OpenRa.Game/Traits/EngineerCapture.cs b/OpenRa.Game/Traits/EngineerCapture.cs
new file mode 100644
index 0000000000..31e9b8eaac
--- /dev/null
+++ b/OpenRa.Game/Traits/EngineerCapture.cs
@@ -0,0 +1,34 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using OpenRa.Game.Traits.Activities;
+
+namespace OpenRa.Game.Traits
+{
+	class EngineerCapture : IOrder
+	{
+		public const int EngineerDamage = 300;
+
+		public Order IssueOrder(Actor self, int2 xy, MouseInput mi, Actor underCursor)
+		{
+			if (underCursor == null) return null;
+			if (!underCursor.traits.Contains<Building>()) return null;
+			
+			// todo: other bits
+
+			return new Order(underCursor.Health <= EngineerDamage ? "Capture" : "Enter",
+				self, underCursor, int2.Zero, null);
+		}
+
+		public void ResolveOrder(Actor self, Order order)
+		{
+			if (order.OrderString == "Enter" || order.OrderString == "Capture")
+			{
+				self.CancelActivity();
+				self.QueueActivity(new Move(order.TargetActor, 2));
+				self.QueueActivity(new CaptureBuilding(order.TargetActor));
+			}
+		}
+	}
+}
diff --git a/units.ini b/units.ini
index 156c0f25da..3e66b0dd62 100755
--- a/units.ini
+++ b/units.ini
@@ -564,7 +564,7 @@ FireDelay=8
 LongDesc=Advanced Anti-infantry unit.\n  Strong vs Infantry, Buildings\n  Weak vs Vehicles
 [E6]
 Description=Engineer
-Traits=Unit, Mobile, RenderInfantry, TakeCover, SquishByTank
+Traits=Unit, Mobile, EngineerCapture, RenderInfantry, TakeCover, SquishByTank
 Voice=EngineerVoice
 LongDesc=Infiltrates and captures enemy structures.\n  Strong vs Nothing\n  Weak vs Everything
 [SPY]