diff --git a/src/gfxinit.cpp b/src/gfxinit.cpp
index 39f735edaf..17a13a0e47 100644
--- a/src/gfxinit.cpp
+++ b/src/gfxinit.cpp
@@ -50,6 +50,7 @@ static const SpriteID * const _landscape_spriteindexes[] = {
 /** file index of first user-added GRF file */
 int _first_user_grf_file_index;
 int _opengfx_grf_file_index;
+int _progsig_grf_file_index;
 
 /**
  * Load an old fashioned GRF file.
@@ -182,8 +183,14 @@ static void LoadSpriteTables()
 	LoadGrfFile(used_set->files[GFT_BASE].filename, 0, i++);
 
 	/* Progsignal sprites. */
+	_progsig_grf_file_index = i;
 	LoadGrfFile("progsignals.grf", SPR_PROGSIGNAL_BASE, i++);
 
+	/* Fill duplicate programmable signal graphics sprite block */
+	for (uint i = 0; i < PROGSIGNAL_SPRITE_COUNT; i++) {
+		DupSprite(SPR_PROGSIGNAL_BASE + i, SPR_DUP_PROGSIGNAL_BASE + i);
+	}
+
 	/* Tracerestrict sprites. */
 	LoadGrfFile("tracerestrict.grf", SPR_TRACERESTRICT_BASE, i++);
 
diff --git a/src/rail_cmd.cpp b/src/rail_cmd.cpp
index 81865bc80a..73ee395688 100644
--- a/src/rail_cmd.cpp
+++ b/src/rail_cmd.cpp
@@ -2357,33 +2357,43 @@ void DrawSingleSignal(TileIndex tile, const RailtypeInfo *rti, Track track, Sign
 	uint x = TileX(tile) * TILE_SIZE + SignalPositions[side][pos].x;
 	uint y = TileY(tile) * TILE_SIZE + SignalPositions[side][pos].y;
 
-	SpriteID sprite = GetCustomSignalSprite(rti, tile, type, variant, condition);
-	bool is_custom_sprite = (sprite != 0);
-	if (sprite != 0) {
-		sprite += image;
+	SpriteID sprite;
+	bool is_custom_sprite;
+	if (type == SIGTYPE_PROG) {
+		if (variant == SIG_SEMAPHORE) {
+			sprite = SPR_PROGSIGNAL_BASE + image * 2 + condition;
+		} else {
+			sprite = SPR_PROGSIGNAL_BASE + 16 + image * 2 + condition;
+		}
+		extern int _progsig_grf_file_index;
+		is_custom_sprite = (int) GetOriginFileSlot(sprite) != _progsig_grf_file_index;
 	} else {
-		/* Normal electric signals are stored in a different sprite block than all other signals. */
-		sprite = (type == SIGTYPE_NORMAL && variant == SIG_ELECTRIC) ? SPR_ORIGINAL_SIGNALS_BASE : SPR_SIGNALS_BASE - 16;
-		sprite += type * 16 + variant * 64 + image * 2 + condition + (IsSignalSpritePBS(type) ? 64 : 0);
-	}
+		sprite = GetCustomSignalSprite(rti, tile, type, variant, condition);
+		is_custom_sprite = (sprite != 0);
+		if (sprite != 0) {
+			sprite += image;
+		} else {
+			/* Normal electric signals are stored in a different sprite block than all other signals. */
+			sprite = (type == SIGTYPE_NORMAL && variant == SIG_ELECTRIC) ? SPR_ORIGINAL_SIGNALS_BASE : SPR_SIGNALS_BASE - 16;
+			sprite += type * 16 + variant * 64 + image * 2 + condition + (IsSignalSpritePBS(type) ? 64 : 0);
+		}
 
-	if (type == SIGTYPE_PROG && variant == SIG_SEMAPHORE) {
-		sprite = SPR_PROGSIGNAL_BASE + image * 2 + condition;
-		is_custom_sprite = false;
-	} else if (type == SIGTYPE_PROG && variant == SIG_ELECTRIC) {
-		sprite = SPR_PROGSIGNAL_BASE + 16 + image * 2 + condition;
-		is_custom_sprite = false;
-	} else {
-		int origin_slot = GetOriginFileSlot(sprite);
-		extern int _first_user_grf_file_index;
-		extern int _opengfx_grf_file_index;
-		if (!is_custom_sprite) is_custom_sprite = origin_slot != _opengfx_grf_file_index && (origin_slot >= _first_user_grf_file_index);
+		if (!is_custom_sprite) {
+			int origin_slot = GetOriginFileSlot(sprite);
+			extern int _first_user_grf_file_index;
+			extern int _opengfx_grf_file_index;
+			is_custom_sprite = origin_slot != _opengfx_grf_file_index && (origin_slot >= _first_user_grf_file_index);
+		}
 	}
 
 	if (is_custom_sprite && show_restricted && _settings_client.gui.show_restricted_signal_default) {
 		/* Use duplicate sprite block, instead of GRF-specified signals */
-		sprite = (type == SIGTYPE_NORMAL && variant == SIG_ELECTRIC) ? SPR_DUP_ORIGINAL_SIGNALS_BASE : SPR_DUP_SIGNALS_BASE - 16;
-		sprite += type * 16 + variant * 64 + image * 2 + condition + (IsSignalSpritePBS(type) ? 64 : 0);
+		if (type == SIGTYPE_PROG) {
+			sprite += SPR_DUP_PROGSIGNAL_BASE - SPR_PROGSIGNAL_BASE;
+		} else {
+			sprite = (type == SIGTYPE_NORMAL && variant == SIG_ELECTRIC) ? SPR_DUP_ORIGINAL_SIGNALS_BASE : SPR_DUP_SIGNALS_BASE - 16;
+			sprite += type * 16 + variant * 64 + image * 2 + condition + (IsSignalSpritePBS(type) ? 64 : 0);
+		}
 		is_custom_sprite = false;
 	}
 
diff --git a/src/table/sprites.h b/src/table/sprites.h
index 133a2eb228..09d772c3ad 100644
--- a/src/table/sprites.h
+++ b/src/table/sprites.h
@@ -312,9 +312,10 @@ static const uint16 PALETTE_SPRITE_COUNT = 1;
 /* Programmable signal sprites */
 static const SpriteID SPR_PROGSIGNAL_BASE = SPR_PALETTE_BASE + PALETTE_SPRITE_COUNT;
 static const uint16 PROGSIGNAL_SPRITE_COUNT = 32;
+static const SpriteID SPR_DUP_PROGSIGNAL_BASE = SPR_PROGSIGNAL_BASE + PROGSIGNAL_SPRITE_COUNT;
 
 /* Zoning sprites */
-static const SpriteID SPR_ZONING_INNER_HIGHLIGHT_BASE       = SPR_PROGSIGNAL_BASE + PROGSIGNAL_SPRITE_COUNT;
+static const SpriteID SPR_ZONING_INNER_HIGHLIGHT_BASE       = SPR_DUP_PROGSIGNAL_BASE + PROGSIGNAL_SPRITE_COUNT;
 static const uint16 ZONING_INNER_HIGHLIGHT_SPRITE_COUNT = 32;
 static const SpriteID SPR_ZONING_INNER_HIGHLIGHT_RED        = SPR_ZONING_INNER_HIGHLIGHT_BASE + 19;
 static const SpriteID SPR_ZONING_INNER_HIGHLIGHT_GREEN      = SPR_ZONING_INNER_HIGHLIGHT_BASE + 20;