diff --git a/OpenRA.Mods.Common/Traits/Buildings/Bridge.cs b/OpenRA.Mods.Common/Traits/Buildings/Bridge.cs
index e534ab456e..7b390faccb 100644
--- a/OpenRA.Mods.Common/Traits/Buildings/Bridge.cs
+++ b/OpenRA.Mods.Common/Traits/Buildings/Bridge.cs
@@ -47,7 +47,18 @@ namespace OpenRA.Mods.Common.Traits
 
 		public object Create(ActorInitializer init) { return new Bridge(init.Self, this); }
 
-		public void RulesetLoaded(Ruleset rules, ActorInfo ai) { DemolishWeaponInfo = rules.Weapons[DemolishWeapon.ToLowerInvariant()]; }
+		public void RulesetLoaded(Ruleset rules, ActorInfo ai)
+		{
+			if (string.IsNullOrEmpty(DemolishWeapon))
+				throw new YamlException("A value for DemolishWeapon of a Bridge trait is missing.");
+
+			WeaponInfo weapon;
+			var weaponToLower = DemolishWeapon.ToLowerInvariant();
+			if (!rules.Weapons.TryGetValue(weaponToLower, out weapon))
+				throw new YamlException("Weapons Ruleset does not contain an entry '{0}'".F(weaponToLower));
+
+			DemolishWeaponInfo = weapon;
+		}
 
 		public IEnumerable<Pair<ushort, int>> Templates
 		{