diff --git a/OpenRA.Mods.RA/Immobile.cs b/OpenRA.Mods.RA/Immobile.cs
index 424395b6c7..8fa3d6a8c1 100644
--- a/OpenRA.Mods.RA/Immobile.cs
+++ b/OpenRA.Mods.RA/Immobile.cs
@@ -16,20 +16,27 @@ namespace OpenRA.Mods.RA
 {
 	class ImmobileInfo : ITraitInfo, IOccupySpaceInfo
 	{
-		public object Create(ActorInitializer init) { return new Immobile(init); }
+		public readonly bool OccupiesSpace = true;
+		public object Create(ActorInitializer init) { return new Immobile(init, this); }
 	}
 
 	class Immobile : IOccupySpace, ISync, INotifyAddedToWorld, INotifyRemovedFromWorld
 	{
 		[Sync] readonly CPos location;
+		readonly IEnumerable<Pair<CPos, SubCell>> occupied;
 
-		public Immobile(ActorInitializer init)
+		public Immobile(ActorInitializer init, ImmobileInfo info)
 		{
 			this.location = init.Get<LocationInit, CPos>();
+
+			if (info.OccupiesSpace)
+				occupied = new [] { Pair.New(TopLeft, SubCell.FullCell) };
+			else
+				occupied = new Pair<CPos, SubCell>[0];
 		}
 
 		public CPos TopLeft { get { return location; } }
-		public IEnumerable<Pair<CPos, SubCell>> OccupiedCells() { yield break; }
+		public IEnumerable<Pair<CPos, SubCell>> OccupiedCells() { return occupied; }
 		public WPos CenterPosition { get { return location.CenterPosition; } }
 
 		public void AddedToWorld(Actor self)
diff --git a/OpenRA.Mods.RA/Mine.cs b/OpenRA.Mods.RA/Mine.cs
index 4e7f24d662..04651e95db 100644
--- a/OpenRA.Mods.RA/Mine.cs
+++ b/OpenRA.Mods.RA/Mine.cs
@@ -25,17 +25,15 @@ namespace OpenRA.Mods.RA
 		public object Create(ActorInitializer init) { return new Mine(init, this); }
 	}
 
-	class Mine : ICrushable, IOccupySpace, ISync, INotifyAddedToWorld, INotifyRemovedFromWorld
+	class Mine : ICrushable
 	{
 		readonly Actor self;
 		readonly MineInfo info;
-		[Sync] readonly CPos location;
 
 		public Mine(ActorInitializer init, MineInfo info)
 		{
 			this.self = init.self;
 			this.info = info;
-			this.location = init.Get<LocationInit,CPos>();
 		}
 
 		public void WarnCrush(Actor crusher) {}
@@ -56,25 +54,6 @@ namespace OpenRA.Mods.RA
 		{
 			return info.CrushClasses.Intersect(crushClasses).Any();
 		}
-
-		public CPos TopLeft { get { return location; } }
-
-		public IEnumerable<Pair<CPos, SubCell>> OccupiedCells() { yield return Pair.New(TopLeft, SubCell.FullCell); }
-		public WPos CenterPosition { get { return location.CenterPosition; } }
-
-		public void AddedToWorld(Actor self)
-		{
-			self.World.ActorMap.AddInfluence(self, this);
-			self.World.ActorMap.AddPosition(self, this);
-			self.World.ScreenMap.Add(self);
-		}
-
-		public void RemovedFromWorld(Actor self)
-		{
-			self.World.ActorMap.RemoveInfluence(self, this);
-			self.World.ActorMap.RemovePosition(self, this);
-			self.World.ScreenMap.Remove(self);
-		}
 	}
 
 	/* tag trait for stuff that shouldnt trigger mines */
diff --git a/OpenRA.Utility/UpgradeRules.cs b/OpenRA.Utility/UpgradeRules.cs
index 33770fd3d1..2202893a53 100644
--- a/OpenRA.Utility/UpgradeRules.cs
+++ b/OpenRA.Utility/UpgradeRules.cs
@@ -163,6 +163,17 @@ namespace OpenRA.Utility
 						node.Key = "RenderDisguise";
 				}
 
+				// IOccupySpace was removed from Mine
+				if (engineVersion < 20140320)
+				{
+					if (depth == 0 && node.Value.Nodes.Any(n => n.Key == "Mine"))
+						node.Value.Nodes.Add(new MiniYamlNode("Immobile", new MiniYaml("", new List<MiniYamlNode>() { new MiniYamlNode("OccupiesSpace", "true") })));
+					else
+						foreach (var i in nodes.Where(n => n.Key == "Immobile"))
+							if (!i.Value.Nodes.Any(n => n.Key == "OccupiesSpace"))
+								i.Value.Nodes.Add(new MiniYamlNode("OccupiesSpace", "false"));
+				}
+
 				UpgradeActorRules(engineVersion, ref node.Value.Nodes, node, depth + 1);
 			}
 		}
diff --git a/mods/cnc/rules/system-actors.yaml b/mods/cnc/rules/system-actors.yaml
index 27a1412a54..9b4fe0aeb8 100644
--- a/mods/cnc/rules/system-actors.yaml
+++ b/mods/cnc/rules/system-actors.yaml
@@ -32,16 +32,19 @@ CRATE:
 
 mpspawn:
 	Immobile:
+		OccupiesSpace: false
 	RenderEditorOnly:
 	BodyOrientation:
 
 waypoint:
 	Immobile:
+		OccupiesSpace: false
 	RenderEditorOnly:
 	BodyOrientation:
 
 CAMERA:
 	Immobile:
+		OccupiesSpace: false
 	Health:
 		HP: 1000
 	RevealsShroud:
diff --git a/mods/d2k/rules/system-actors.yaml b/mods/d2k/rules/system-actors.yaml
index 4542a03daa..4ee97c7222 100644
--- a/mods/d2k/rules/system-actors.yaml
+++ b/mods/d2k/rules/system-actors.yaml
@@ -86,11 +86,13 @@ CRATE:
 
 mpspawn:
 	Immobile:
+		OccupiesSpace: false
 	RenderEditorOnly:
 	BodyOrientation:
 
 waypoint:
 	Immobile:
+		OccupiesSpace: false
 	RenderEditorOnly:
 	BodyOrientation:
 
diff --git a/mods/ra/rules/system-actors.yaml b/mods/ra/rules/system-actors.yaml
index 572fcbd3d6..4a71b389bb 100644
--- a/mods/ra/rules/system-actors.yaml
+++ b/mods/ra/rules/system-actors.yaml
@@ -23,6 +23,8 @@ MINP:
 	TargetableUnit:
 		TargetTypes: Ground
 	BodyOrientation:
+	Immobile:
+		OccupiesSpace: true
 
 MINV:
 	Mine:
@@ -49,6 +51,8 @@ MINV:
 	TargetableUnit:
 		TargetTypes: Ground
 	BodyOrientation:
+	Immobile:
+		OccupiesSpace: true
 
 CRATE:
 	Tooltip:
@@ -122,6 +126,7 @@ CRATE:
 
 CAMERA:
 	Immobile:
+		OccupiesSpace: false
 	Health:
 		HP: 1000
 	RevealsShroud:
@@ -134,6 +139,7 @@ CAMERA:
 
 FLARE:
 	Immobile:
+		OccupiesSpace: false
 	Health:
 		HP: 1000
 	RevealsShroud:
@@ -170,11 +176,13 @@ powerproxy.sonarpulse:
 
 mpspawn:
 	Immobile:
+		OccupiesSpace: false
 	RenderEditorOnly:
 	BodyOrientation:
 
 waypoint:
 	Immobile:
+		OccupiesSpace: false
 	RenderEditorOnly:
 	BodyOrientation:
 
diff --git a/mods/ts/rules/system-actors.yaml b/mods/ts/rules/system-actors.yaml
index 638c103e1a..a2dfd32804 100644
--- a/mods/ts/rules/system-actors.yaml
+++ b/mods/ts/rules/system-actors.yaml
@@ -1,10 +1,12 @@
 mpspawn:
 	Immobile:
+		OccupiesSpace: false
 	RenderEditorOnly:
 	BodyOrientation:
 
 waypoint:
 	Immobile:
+		OccupiesSpace: false
 	RenderEditorOnly:
 	BodyOrientation: