When trying to load the b.128.simutrans.entropy.me.uk game, I get an error when there is a check for a wide tunnel portal (most likely since I acidently used the wrong pak) but, the calc_bild() is called from hausbauer_t lines 488ff before laden_abschliessen. That may be an issue for more than just missing tunnels on load time, and is not needed, since laden_abschliessen will do this again.