Also use custom sprite sorting for catenary pylons under bridges

src/elrail.cpp

@@ -481,14 +481,19 @@ static void DrawRailCatenaryRailway(const TileInfo *ti)
 		 * Remove those (simply by ANDing with allowed, since these markers are never allowed) */
 		if ((PPPallowed[i] & PPPpreferred[i]) != 0) PPPallowed[i] &= PPPpreferred[i];
 
+		ViewportSortableSpriteSpecialFlags special_flags = VSSF_NONE;
+
 		if (IsBridgeAbove(ti->tile)) {
 			Track bridgetrack = GetBridgeAxis(ti->tile) == AXIS_X ? TRACK_X : TRACK_Y;
 			int height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));
 
-			if ((height <= GetTileMaxZ(ti->tile) + 1) &&
+			int max_z = GetTileMaxZ(ti->tile);
+			if ((height <= max_z + 1) &&
 					(i == PCPpositions[bridgetrack][0] || i == PCPpositions[bridgetrack][1])) {
 				SetBit(OverridePCP, i);
 			}
+
+			if (height <= max_z + 1) special_flags = VSSSF_SORT_SPECIAL | VSSSF_SORT_DIAG_VEH;
 		}
 
 		if (PPPallowed[i] != 0 && HasBit(PCPstatus, i) && !HasBit(OverridePCP, i) &&
@@ -508,7 +513,7 @@ static void DrawRailCatenaryRailway(const TileInfo *ti)
 					}
 
 					AddSortableSpriteToDraw(pylon_base + pylon_sprites[temp], PAL_NONE, x, y, 1, 1, BB_HEIGHT_UNDER_BRIDGE,
-						elevation, IsTransparencySet(TO_CATENARY), -1, -1);
+						elevation, IsTransparencySet(TO_CATENARY), -1, -1, 0, nullptr, special_flags);
 
 					break; // We already have drawn a pylon, bail out
 				}

src/viewport_func.h

@@ -76,7 +76,7 @@ enum ViewportSortableSpriteSpecialFlags : uint8_t {
 	VSSF_NONE                      =    0,
 	VSSSF_SORT_SPECIAL             = 0x80, ///< When sorting sprites, if both sprites have this set, special sorting rules apply
 	VSSSF_SORT_SPECIAL_TYPE_MASK   =    1, ///< Mask to use for getting the special type
-	VSSSF_SORT_DIAG_VEH            =    0, ///< This is a vehicle moving diagonally with respect to the tile axes
+	VSSSF_SORT_DIAG_VEH            =    0, ///< This is a vehicle moving diagonally with respect to the tile axes (also used for catenary pylons on diagonal track under bridges for similar reasons)
 	VSSSF_SORT_SORT_BRIDGE_BB      =    1, ///< This is a bridge BB helper sprite
 };
 DECLARE_ENUM_AS_BIT_SET(ViewportSortableSpriteSpecialFlags);