2 files changed, 5 insertions, 2 deletions
diff --git a/src/newgrf_railtype.cpp b/src/newgrf_railtype.cpp
index 872a3a7f6..8a074db97 100644
--- a/src/newgrf_railtype.cpp
+++ b/src/newgrf_railtype.cpp
@@ -100,9 +100,10 @@ RailTypeResolverObject::RailTypeResolverObject(const RailtypeInfo *rti, TileInde
  * @param tile The tile to get the sprite for.
  * @param rtsg The type of sprite to draw.
  * @param content Where are we drawing the tile?
+ * @param [out] num_results If not NULL, return the number of sprites in the spriteset.
  * @return The sprite to draw.
  */
-SpriteID GetCustomRailSprite(const RailtypeInfo *rti, TileIndex tile, RailTypeSpriteGroup rtsg, TileContext context)
+SpriteID GetCustomRailSprite(const RailtypeInfo *rti, TileIndex tile, RailTypeSpriteGroup rtsg, TileContext context, uint *num_results)
 {
 	assert(rtsg < RTSG_END);
 
@@ -112,6 +113,8 @@ SpriteID GetCustomRailSprite(const RailtypeInfo *rti, TileIndex tile, RailTypeSp
 	const SpriteGroup *group = object.Resolve();
 	if (group == NULL || group->GetNumResults() == 0) return 0;
 
+	if (num_results) *num_results = group->GetNumResults();
+
 	return group->GetResult();
 }
 
diff --git a/src/newgrf_railtype.h b/src/newgrf_railtype.h
index 9b00bf5bf..4c68e7d1d 100644
--- a/src/newgrf_railtype.h
+++ b/src/newgrf_railtype.h
@@ -44,7 +44,7 @@ struct RailTypeResolverObject : public ResolverObject {
 	/* virtual */ const SpriteGroup *ResolveReal(const RealSpriteGroup *group) const;
 };
 
-SpriteID GetCustomRailSprite(const RailtypeInfo *rti, TileIndex tile, RailTypeSpriteGroup rtsg, TileContext context = TCX_NORMAL);
+SpriteID GetCustomRailSprite(const RailtypeInfo *rti, TileIndex tile, RailTypeSpriteGroup rtsg, TileContext context = TCX_NORMAL, uint *num_results = NULL);
 SpriteID GetCustomSignalSprite(const RailtypeInfo *rti, TileIndex tile, SignalType type, SignalVariant var, SignalState state, bool gui = false);
 
 uint8 GetReverseRailTypeTranslation(RailType railtype, const GRFFile *grffile);