diff --git a/OpenRa.Game/Traits/Util.cs b/OpenRa.Game/Traits/Util.cs
index 9c42055e3d..bde7f77c59 100755
--- a/OpenRa.Game/Traits/Util.cs
+++ b/OpenRa.Game/Traits/Util.cs
@@ -127,13 +127,14 @@ namespace OpenRa.Game.Traits
 
 		public static float GetEffectiveSpeed(Actor self)
 		{
-			if (!self.Info.Traits.Contains<MobileInfo>()) return 0f;
+			var mi = self.LegacyInfo as LegacyMobileInfo;
+			if (mi == null) return 0f;
 
 			var modifier = self.traits
 				.WithInterface<ISpeedModifier>()
 				.Select(t => t.GetSpeedModifier())
 				.Product();
-			return self.Info.Traits.Get<MobileInfo>().Speed * modifier;
+			return mi.Speed * modifier;
 		}
 
 		public static IActivity SequenceActivities(params IActivity[] acts)