diff --git a/newgrf_engine.c b/newgrf_engine.c
index c6f7be5f02..06c0c11f16 100644
--- a/newgrf_engine.c
+++ b/newgrf_engine.c
@@ -405,7 +405,7 @@ static const SpriteGroup *GetVehicleSpriteGroup(EngineID engine, const Vehicle *
 	return group;
 }
 
-int GetCustomEngineSprite(EngineID engine, const Vehicle* v, Direction direction)
+SpriteID GetCustomEngineSprite(EngineID engine, const Vehicle* v, Direction direction)
 {
 	const SpriteGroup *group;
 	const RealSpriteGroup *rsg;
diff --git a/newgrf_engine.h b/newgrf_engine.h
index 6f05d81333..d215377714 100644
--- a/newgrf_engine.h
+++ b/newgrf_engine.h
@@ -17,7 +17,7 @@ VARDEF const uint32 cargo_classes[16];
 void SetWagonOverrideSprites(EngineID engine, struct SpriteGroup *group, byte *train_id, int trains);
 void SetCustomEngineSprites(EngineID engine, byte cargo, struct SpriteGroup *group);
 // loaded is in percents, overriding_engine 0xffff is none
-int GetCustomEngineSprite(EngineID engine, const Vehicle* v, Direction direction);
+SpriteID GetCustomEngineSprite(EngineID engine, const Vehicle* v, Direction direction);
 
 void SetEngineGRF(EngineID engine, uint32 grfid);
 uint32 GetEngineGRFID(EngineID engine);