From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=BAYES_20,FREEMAIL_FROM autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 115aec,732030daa45ab98a X-Google-Attributes: gid115aec,public X-Google-Thread: 103376,732030daa45ab98a X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-04-28 10:51:03 PST Path: newsfeed.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed00.sul.t-online.de!newsmm00.sul.t-online.com!t-online.de!news.t-online.com!not-for-mail From: Matthias Andree Newsgroups: comp.lang.ada,comp.realtime Subject: Re: European train deaths Followup-To: comp.lang.ada Date: 28 Apr 2001 02:38:29 +0200 Organization: Badly suffering from World Wide Waiting, Inc. Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: news.t-online.com 988480007 07 1876 MDDrSUdSRAZpj 010428 17:46:47 X-Complaints-To: abuse@t-online.com X-Sender: 320030182200-0001@t-dialin.net User-Agent: Gnus/5.0808 (Gnus v5.8.8) Emacs/20.7 Xref: newsfeed.google.com comp.lang.ada:7020 comp.realtime:2438 Date: 2001-04-28T02:38:29+02:00 List-Id: Colin_Paul_Gloster@ACM.org (Colin Paul Gloster) writes: > Something which occured to me only yesterday (unless I cleanly > forgot before) is that Ada and formal methods are used for > European train systems and so these may be involved in some > of the spate of fatal crashes over the last circa two years > in the U.K.; Nope, AFAI have information about UK train accidents, at least one (near London in 1996 or when that was) was caused by a driver's fault. In Germany, the Deutsche Bundesbahn has - among other systems "InduSi" and "SiFa", systems that prevent a train from entering a "block" (track segment between two signals) which is red. This system was not in place or working properly in at least one of the accidents in the UK. If the driver fails to stop the train, the train will stop anyways (several signals transmitted inductively), this cannot be overriden by the driver. Should the driver fall asleep, die, leave his seat, the train will trigger an emergency stop procedure c. 30 s after the incident. I don't know if speed limits can be enforced in a similar manner, I think they can, see below. As to some of the major German train accidents, on the big ICE disaster in Eschede, there was a mechanical defect. In a recent other major train accident in Western Germany (was it Emmerich? Not sure) the driver went much too fast through a detour (which went around track constructions or maintenance), with 120 km/h with 40 km/h allowed. In Wuppertal, where the Schwebebahn dropped off its tracks and fell into the Wupper river, workers had forgotten to remove a track clamp which is used to prevent a train from proceeding through a track construction. In Belgium (which has three official languages), there was a communication problem since the driver did not properly understand the warning issued to him. I believe there's nothing Ada could do about these incidents. I cannot tell about the Eschede disaster since I believe the last words aren't yet spoken on that case. -- Matthias Andree