--- a/src/industry.h	Sat Aug 25 20:32:18 2007 +0000
+++ b/src/industry.h	Sun Aug 26 00:23:32 2007 +0000
@@ -222,9 +222,18 @@
 
 static inline IndustryGfx GetTranslatedIndustryTileID(IndustryGfx gfx)
 {
-	assert(gfx < INVALID_INDUSTRYTILE);
-	const IndustryTileSpec *it = &_industry_tile_specs[gfx];
-	return it->grf_prop.override == INVALID_INDUSTRYTILE ? gfx : it->grf_prop.override;
+	/* the 0xFF should be GFX_WATERTILE_SPECIALCHECK but for reasons of include mess,
+	 * we'll simplify the writing.
+	 * Basically, the first test is required since the GFX_WATERTILE_SPECIALCHECK value
+	 * will never be assigned as a tile index and is only required in order to do some
+	 * tests while building the industry (as in WATER REQUIRED */
+	if (gfx != 0xFF) {
+		assert(gfx < INVALID_INDUSTRYTILE);
+		const IndustryTileSpec *it = &_industry_tile_specs[gfx];
+		return it->grf_prop.override == INVALID_INDUSTRYTILE ? gfx : it->grf_prop.override;
+	} else {
+		return gfx;
+	}
 }
 
 /* smallmap_gui.cpp */