diff --git a/src/newgrf_industries.h b/src/newgrf_industries.h
--- a/src/newgrf_industries.h
+++ b/src/newgrf_industries.h
@@ -10,5 +10,6 @@
 
 uint32 IndustryGetVariable(const ResolverObject *object, byte variable, byte parameter, bool *available);
 uint16 GetIndustryCallback(uint16 callback, uint32 param1, uint32 param2, Industry *industry, TileIndex tile);
+uint32 GetIndustryIDAtOffset(TileIndex new_tile, TileIndex old_tile, const Industry *i);
 
 #endif /* NEWGRF_INDUSTRIES_H */