diff --git a/src/hardware/hw_main.c b/src/hardware/hw_main.c
index 4d5b136cf..9d0dc91b0 100644
--- a/src/hardware/hw_main.c
+++ b/src/hardware/hw_main.c
@@ -1466,11 +1466,14 @@ static void HWR_ProcessSeg(void) // Sort of like GLWall::Process in GZDoom
 					blendmode = PF_Translucent;
 					break;
 				default:
-					if (gl_linedef->alpha >= 0 && gl_linedef->alpha < FRACUNIT)
-						blendmode = HWR_TranstableToAlpha(R_GetLinedefTransTable(gl_linedef->alpha), &Surf);
+				{
+					transnum_t transtable = R_GetLinedefTransTable(gl_linedef);
+					if (transtable != NUMTRANSMAPS)
+						blendmode = HWR_TranstableToAlpha(transtable, &Surf);
 					else
 						blendmode = PF_Masked;
 					break;
+				}
 			}
 
 			if (gl_curline->polyseg && gl_curline->polyseg->translucency > 0)
diff --git a/src/r_segs.c b/src/r_segs.c
index a848dd884..a646ff440 100644
--- a/src/r_segs.c
+++ b/src/r_segs.c
@@ -270,9 +270,23 @@ static void R_Render2sidedMultiPatchColumn(column_t *column)
 	}
 }
 
-transnum_t R_GetLinedefTransTable(fixed_t alpha)
+transnum_t R_GetLinedefTransTable(line_t *ldef)
 {
-	return (20*(FRACUNIT - alpha - 1) + FRACUNIT) >> (FRACBITS+1);
+	transnum_t transnum = NUMTRANSMAPS; // Send back NUMTRANSMAPS for none
+	fixed_t alpha = ldef->alpha;
+	if (alpha > 0 && alpha < FRACUNIT)
+		transnum = (20*(FRACUNIT - alpha - 1) + FRACUNIT) >> (FRACBITS+1);
+	else
+	{
+		switch (ldef->special)
+		{
+			case 910: transnum = tr_transadd; break;
+			case 911: transnum = tr_transsub; break;
+			default: transnum = NUMTRANSMAPS; break;
+		}
+	}
+
+	return transnum;
 }
 
 void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2)
@@ -289,6 +303,7 @@ void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2)
 	INT32 times, repeats;
 	INT64 overflow_test;
 	INT32 range;
+	transnum_t transtable = NUMTRANSMAPS;
 
 	// Calculate light table.
 	// Use different light tables
@@ -305,9 +320,10 @@ void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2)
 	if (!ldef->alpha)
 		return;
 
-	if (ldef->alpha > 0 && ldef->alpha < FRACUNIT)
+	transtable = R_GetLinedefTransTable(ldef);
+	if (transtable != NUMTRANSMAPS)
 	{
-		dc_transmap = transtables + ((R_GetLinedefTransTable(ldef->alpha) - 1) << FF_TRANSSHIFT);
+		dc_transmap = transtables + ((transtable - 1) << FF_TRANSSHIFT);
 		colfunc = colfuncs[COLDRAWFUNC_FUZZY];
 
 	}
diff --git a/src/r_segs.h b/src/r_segs.h
index ace5711d4..6a79047e0 100644
--- a/src/r_segs.h
+++ b/src/r_segs.h
@@ -18,7 +18,7 @@
 #pragma interface
 #endif
 
-transnum_t R_GetLinedefTransTable(fixed_t alpha);
+transnum_t R_GetLinedefTransTable(line_t *line);
 void R_RenderMaskedSegRange(drawseg_t *ds, INT32 x1, INT32 x2);
 void R_RenderThickSideRange(drawseg_t *ds, INT32 x1, INT32 x2, ffloor_t *pffloor);
 void R_StoreWallRange(INT32 start, INT32 stop);