diff --git a/OpenRA.Mods.RA/Activities/RepairBridge.cs b/OpenRA.Mods.RA/Activities/RepairBridge.cs
index 7d770111c5..7da09d5046 100644
--- a/OpenRA.Mods.RA/Activities/RepairBridge.cs
+++ b/OpenRA.Mods.RA/Activities/RepairBridge.cs
@@ -12,25 +12,24 @@ using OpenRA.Traits;
 
 namespace OpenRA.Mods.RA.Activities
 {
-	class RepairBridge : Activity
+	class RepairBridge : Enter
 	{
-		Target target;
+		readonly BridgeHut hut;
 
-		public RepairBridge(Actor target) { this.target = Target.FromActor(target); }
+		public RepairBridge(Actor self, Actor target)
+			: base(self, target) { hut = target.Trait<BridgeHut>(); }
 
-		public override Activity Tick(Actor self)
+		protected override bool CanReserve(Actor self)
 		{
-			if (IsCanceled || target.Type != TargetType.Actor)
-				return NextActivity;
+			return hut.BridgeDamageState != DamageState.Undamaged;
+		}
 
-			var hut = target.Actor.Trait<BridgeHut>();
+		protected override void OnInside(Actor self)
+		{
 			if (hut.BridgeDamageState == DamageState.Undamaged)
-				return NextActivity;
-
+				return;
 			hut.Repair(self);
 			self.Destroy();
-
-			return this;
 		}
 	}
 }
diff --git a/OpenRA.Mods.RA/Activities/RepairBuilding.cs b/OpenRA.Mods.RA/Activities/RepairBuilding.cs
index b5a813e138..92a3dec918 100644
--- a/OpenRA.Mods.RA/Activities/RepairBuilding.cs
+++ b/OpenRA.Mods.RA/Activities/RepairBuilding.cs
@@ -12,25 +12,29 @@ using OpenRA.Traits;
 
 namespace OpenRA.Mods.RA.Activities
 {
-	class RepairBuilding : Activity
+	class RepairBuilding : Enter
 	{
-		Target target;
+		readonly Actor target;
+		readonly Health health;
 
-		public RepairBuilding(Actor target) { this.target = Target.FromActor(target); }
-
-		public override Activity Tick(Actor self)
+		public RepairBuilding(Actor self, Actor target)
+			: base(self, target)
 		{
-			if (IsCanceled || target.Type != TargetType.Actor)
-				return NextActivity;
+			this.target = target;
+			health = target.Trait<Health>();
+		}
 
-			var health = target.Actor.Trait<Health>();
+		protected override bool CanReserve(Actor self)
+		{
+			return health.DamageState != DamageState.Undamaged;
+		}
+
+		protected override void OnInside(Actor self)
+		{
 			if (health.DamageState == DamageState.Undamaged)
-				return NextActivity;
-
-			target.Actor.InflictDamage(self, -health.MaxHP, null);
+				return;
+			target.InflictDamage(self, -health.MaxHP, null);
 			self.Destroy();
-
-			return this;
 		}
 	}
 }
diff --git a/OpenRA.Mods.RA/EngineerRepair.cs b/OpenRA.Mods.RA/EngineerRepair.cs
index 60c5cdde8b..eca7376f94 100644
--- a/OpenRA.Mods.RA/EngineerRepair.cs
+++ b/OpenRA.Mods.RA/EngineerRepair.cs
@@ -78,7 +78,7 @@ namespace OpenRA.Mods.RA
 				self.CancelActivity();
 
 			self.SetTargetLine(target, Color.Yellow);
-			self.QueueActivity(new Enter(self, target.Actor, new RepairBuilding(target.Actor)));
+			self.QueueActivity(new RepairBuilding(self, target.Actor));
 		}
 
 		class EngineerRepairOrderTargeter : UnitOrderTargeter
diff --git a/OpenRA.Mods.RA/RepairsBridges.cs b/OpenRA.Mods.RA/RepairsBridges.cs
index b3d8087042..ac1bdbaf36 100644
--- a/OpenRA.Mods.RA/RepairsBridges.cs
+++ b/OpenRA.Mods.RA/RepairsBridges.cs
@@ -59,7 +59,7 @@ namespace OpenRA.Mods.RA
 				self.SetTargetLine(Target.FromOrder(self.World, order), Color.Yellow);
 
 				self.CancelActivity();
-				self.QueueActivity(new Enter(self, order.TargetActor, new RepairBridge(order.TargetActor)));
+				self.QueueActivity(new RepairBridge(self, order.TargetActor));
 			}
 		}