diff --git a/docs/rh-log.txt b/docs/rh-log.txt
index 08263f075..f50aec69f 100644
--- a/docs/rh-log.txt
+++ b/docs/rh-log.txt
@@ -1,3 +1,6 @@
+October 10, 2009  (Changes by Graf Zahl)
+- Added MF6_NOTRIGGER flag that disables all line actions for an actor.
+
 October 9, 2009  (Changes by Graf Zahl)
 - Added Gez's seeker missile submission.
 - Added Gez's thing activation submission.
diff --git a/src/actor.h b/src/actor.h
index 587297f77..0b9605def 100644
--- a/src/actor.h
+++ b/src/actor.h
@@ -316,6 +316,7 @@ enum
 	MF6_ARMED			= 0x00002000,	// From MBF: Object is armed (for MF6_TOUCHY objects)
 	MF6_FALLING			= 0x00004000,	// From MBF: Object is falling (for pseudotorque simulation)
 	MF6_LINEDONE		= 0x00008000,	// From MBF: Object has already run a line effect
+	MF6_NOTRIGGER		= 0x00010000,	// actor cannot trigger any line actions
 
 // --- mobj.renderflags ---
 
diff --git a/src/p_acs.cpp b/src/p_acs.cpp
index 456c5553b..91c471bb6 100644
--- a/src/p_acs.cpp
+++ b/src/p_acs.cpp
@@ -2428,6 +2428,7 @@ enum
 	APROP_Species		= 20,
 	APROP_NameTag		= 21,
 	APROP_Score			= 22,
+	APROP_Notrigger		= 23,
 };	
 
 // These are needed for ACS's APROP_RenderStyle
@@ -2519,6 +2520,10 @@ void DLevelScript::DoSetActorProperty (AActor *actor, int property, int value)
 		if (value) actor->flags3 |= MF3_NOTARGET; else actor->flags3 &= ~MF3_NOTARGET;
 		break;
 
+	case APROP_Notrigger:
+		if (value) actor->flags6 |= MF6_NOTRIGGER; else actor->flags6 &= ~MF6_NOTRIGGER;
+		break;
+
 	case APROP_JumpZ:
 		if (actor->IsKindOf (RUNTIME_CLASS (APlayerPawn)))
 			static_cast<APlayerPawn *>(actor)->JumpZ = value;
@@ -2638,6 +2643,7 @@ int DLevelScript::GetActorProperty (int tid, int property)
 	case APROP_Frightened:	return !!(actor->flags4 & MF4_FRIGHTENED);
 	case APROP_Friendly:	return !!(actor->flags & MF_FRIENDLY);
 	case APROP_Notarget:	return !!(actor->flags3 & MF3_NOTARGET);
+	case APROP_Notrigger:	return !!(actor->flags6 & MF6_NOTRIGGER);
 	case APROP_SpawnHealth: if (actor->IsKindOf (RUNTIME_CLASS (APlayerPawn)))
 							{
 								return static_cast<APlayerPawn *>(actor)->MaxHealth;
@@ -2694,6 +2700,7 @@ int DLevelScript::CheckActorProperty (int tid, int property, int value)
 		case APROP_Frightened:
 		case APROP_Friendly:
 		case APROP_Notarget:
+		case APROP_Notrigger:
 			return (GetActorProperty(tid, property) == (!!value));
 
 		// Strings are not covered by GetActorProperty, so make the check here
diff --git a/src/p_enemy.cpp b/src/p_enemy.cpp
index 7e3bb0b26..d25ae3de0 100644
--- a/src/p_enemy.cpp
+++ b/src/p_enemy.cpp
@@ -583,15 +583,19 @@ bool P_Move (AActor *actor)
 		line_t *ld;
 		int good = 0;
 		
-		while (spechit.Pop (ld))
+		if (!(actor->flags6 & MF6_NOTRIGGER))
 		{
-			// [RH] let monsters push lines, as well as use them
-			if (((actor->flags4 & MF4_CANUSEWALLS) && P_ActivateLine (ld, actor, 0, SPAC_Use)) ||
-				((actor->flags2 & MF2_PUSHWALL) && P_ActivateLine (ld, actor, 0, SPAC_Push)))
+			while (spechit.Pop (ld))
 			{
-				good |= ld == actor->BlockingLine ? 1 : 2;
+				// [RH] let monsters push lines, as well as use them
+				if (((actor->flags4 & MF4_CANUSEWALLS) && P_ActivateLine (ld, actor, 0, SPAC_Use)) ||
+					((actor->flags2 & MF2_PUSHWALL) && P_ActivateLine (ld, actor, 0, SPAC_Push)))
+				{
+					good |= ld == actor->BlockingLine ? 1 : 2;
+				}
 			}
 		}
+		else spechit.Clear();
 		return good && ((pr_opendoor() >= 203) ^ (good & 1));
 	}
 	else
diff --git a/src/p_map.cpp b/src/p_map.cpp
index 3f04ce0d1..e8c401bc1 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -1519,7 +1519,7 @@ void P_FakeZMovement (AActor *mo)
 
 static void CheckForPushSpecial (line_t *line, int side, AActor *mobj)
 {
-	if (line->special)
+	if (line->special && !(mobj->flags6 & MF6_NOTRIGGER))
 	{
 		if (mobj->flags2 & MF2_PUSHWALL)
 		{
@@ -1795,7 +1795,7 @@ bool P_TryMove (AActor *thing, fixed_t x, fixed_t y,
 			// see if the line was crossed
 			side = P_PointOnLineSide (thing->x, thing->y, ld);
 			oldside = P_PointOnLineSide (oldx, oldy, ld);
-			if (side != oldside && ld->special)
+			if (side != oldside && ld->special && !(thing->flags6 & MF6_NOTRIGGER))
 			{
 				if (thing->player)
 				{
@@ -3231,12 +3231,20 @@ AActor *P_LineAttack (AActor *t1, angle_t angle, fixed_t distance,
 		t1->player->ReadyWeapon != NULL &&
 		(t1->player->ReadyWeapon->flags2 & MF2_THRUGHOST));
 
+	AActor *puffDefaults = GetDefaultByType (pufftype);
+
+	int tflags;
+	if (puffDefaults != NULL && puffDefaults->flags6 & MF6_NOTRIGGER) tflags = TRACE_NoSky;
+	else tflags = TRACE_NoSky|TRACE_Impact;
+
 	if (!Trace (t1->x, t1->y, shootz, t1->Sector, vx, vy, vz, distance,
 		MF_SHOOTABLE, ML_BLOCKEVERYTHING, t1, trace,
-		TRACE_NoSky|TRACE_Impact, hitGhosts ? CheckForGhost : CheckForSpectral))
+		tflags, hitGhosts ? CheckForGhost : CheckForSpectral))
 	{ // hit nothing
-		AActor *puffDefaults = GetDefaultByType (pufftype);
-		if (puffDefaults->ActiveSound)
+		if (puffDefaults == NULL)
+		{
+		}
+		else if (puffDefaults->ActiveSound)
 		{ // Play miss sound
 			S_Sound (t1, CHAN_WEAPON, puffDefaults->ActiveSound, 1, ATTN_NORM);
 		}
@@ -3629,22 +3637,28 @@ void P_RailAttack (AActor *source, int damage, int offset, int color1, int color
 	start.Y = FIXED2FLOAT(y1);
 	start.Z = FIXED2FLOAT(shootz);
 
+	int flags;
+
+	AActor *puffDefaults = puffclass == NULL? NULL : GetDefaultByType (puffclass);
+
+	if (puffDefaults != NULL && puffDefaults->flags6 & MF6_NOTRIGGER) flags = 0;
+	else flags = TRACE_PCross|TRACE_Impact;
+
 	if (pierce)
 	{
 		Trace (x1, y1, shootz, source->Sector, vx, vy, vz,
 			8192*FRACUNIT, MF_SHOOTABLE, ML_BLOCKEVERYTHING, source, trace,
-			TRACE_PCross|TRACE_Impact, ProcessRailHit);
+			flags, ProcessRailHit);
 	}
 	else
 	{
 		Trace (x1, y1, shootz, source->Sector, vx, vy, vz,
 			8192*FRACUNIT, MF_SHOOTABLE, ML_BLOCKEVERYTHING, source, trace,
-			TRACE_PCross|TRACE_Impact, ProcessNoPierceRailHit);
+			flags, ProcessNoPierceRailHit);
 	}
 
 	// Hurt anything the trace hit
 	unsigned int i;
-	AActor *puffDefaults = puffclass == NULL? NULL : GetDefaultByType (puffclass);
 	FName damagetype = (puffDefaults == NULL || puffDefaults->DamageType == NAME_None) ? FName(NAME_Railgun) : puffDefaults->DamageType;
 
 	// used as damage inflictor
diff --git a/src/thingdef/thingdef_data.cpp b/src/thingdef/thingdef_data.cpp
index 89741fca6..f4f782464 100644
--- a/src/thingdef/thingdef_data.cpp
+++ b/src/thingdef/thingdef_data.cpp
@@ -223,6 +223,7 @@ static FFlagDef ActorFlags[]=
 	DEFINE_FLAG(MF6, CANJUMP, AActor, flags6),
 	DEFINE_FLAG(MF6, JUMPDOWN, AActor, flags6),
 	DEFINE_FLAG(MF6, VULNERABLE, AActor, flags6),
+	DEFINE_FLAG(MF6, NOTRIGGER, AActor, flags6),
 
 	// Effect flags
 	DEFINE_FLAG(FX, VISIBILITYPULSE, AActor, effects),