stuving
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« Reply #75 on: November 15, 2015, 20:58:42 » |
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The test phase using this instrumented TGV▸ -Est train started at the end of September and runs to the end of the year, so is only about half-way through. This first part is described as proving the line at increasing speed, from 160 km/hr up to the full train and line speed of 320 km/hr and then 10% higher (352 km/hr; hence the figure of 350 km/hr that has been quoted). The site of the derailment is on a curve with a radius of about 1.3 km and just over 1 km from where it joins the existing "classic" line for the run into Strasbourg. The five "missing" persons are now believed not to have been on board, so the casualty number is as in that last report: 11 killed and 5 still critically ill in hospital. One of those killed was a child, and their presence has still not been explained. Other reports suggest this kind of "treat" was common practice, though unofficial. If the tests have in fact reached full speed, that might seem to be the end of testing the track for faults - leaving things like the signalling and power supplies, and running over every piece of trackwork in every direction. Incidentally, on the LGV▸ trains run on the left, so this run was in reverse. (Trains in Alsace run on the right, so the junction just ahead has to accommodate this switch.) The investigators ( SNCF▸ , BEA-TT and gendarmerie) have recovered the train's data recorders, though presumably the signalling system will know its position and speed. The line is equipped with ETCS▸ / ERTMS▸ , but may not be using it at this stage; it also has the older TVM▸ 430 system. BEA-TT do not usually give the same kind of full statement of facts at the start of an inquiry that RAIB▸ does. However, for serious accidents like this one, SNCF will probably do something similar in a few days, and that should give the actual speed and the limit for this curve. According to le Parisien, citing the no. 2 of SNCF R^seau, the speed limit for this bridge is 176 km/hr. They also quote Guillame Pepy as saying that these tests are run with some of the safety systems turned off.
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Worcester_Passenger
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« Reply #76 on: November 16, 2015, 03:20:10 » |
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Incidentally, on the LGV▸ trains run on the left, so this run was in reverse. (Trains in Alsace run on the right, so the junction just ahead has to accommodate this switch.)
There's a schematic diagram of this flying junction at http://florent.brisou.pagesperso-orange.fr/LGVEE2.pdf, down in the bottom right corner.
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Tim
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« Reply #77 on: November 16, 2015, 10:02:50 » |
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Very Sad. Lets wait until the investigation. My suspicion is that they were doing something that they would not be doing in normal passenger service.
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ChrisB
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« Reply #78 on: November 16, 2015, 10:08:47 » |
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With kids on board.
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Tim
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« Reply #79 on: November 16, 2015, 10:42:53 » |
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With kids on board.
I'm not sure what to think about that. Presumably, test trains are not regarded as risky. If they were adults wouldn't be on them either (certainly not 49 of them). Rail engineers are not, in general reckless people and these are supposed to be safe, controlled tests. I don't think that there are categories of tests that have a level of risk that is acceptable for 40 odd adults but unacceptable for the children of those adults. If there is a derailment risk then the test is not safe for anyone to be on board. You can be sure that kids will be banned in future which is a shame because it will prevent parents sharing their pride in their work with their families.
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LiskeardRich
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« Reply #80 on: November 16, 2015, 10:55:36 » |
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It is known These test trains have been running 10% over speed limits with safety equipment off so as it is possible to run at limit plus 10%. The speed at derailment is not confirmed, but the speed limit at location is 160 kph, so plus 10% 176kph. This was around about the 200th test, and all the previous tests ran successfully at the plus 10%.
The train involved was the French version of our NMT train, what kind of staffing does the NMT run with?
The 5 still missing in the above report the BBC» are now saying are accounted for and weren't actually on the train, but others may have been due to the "extra guests".
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All posts are my own personal believes, opinions and understandings!
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stuving
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« Reply #81 on: November 16, 2015, 12:23:30 » |
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An update on the casualties, supposed to be final apart from four people on the danger list in hospital: There were 53 people on board, of whom four were minors. Eleven were killed, but none of the children. All of the rest were classed as "injured", either slightly or now in a stable condition.
As to the risk of tests, in practice that's a matter of rules. This line was not yet signed off as ready for use, so the rules assume there is a risk that should be assessed technically and revised as tests progress. Only staff needed should be present, just as a standard precaution. SNCF▸ house rules would allow invited guests on trains (not necessarily test trains) once the tests are all done but before all the paperwork is finished. That is reasonable enough, but is likely to be challenged once the lawyers get involved.
Normal track measurements can be done on a line open to passenger trains, so the rules for NMT would presumably be those that apply to it as a workplace. This train was a standard TGV▸ with half the carriages refitted with test equipment, so arguably it was not all workplace in that sense. A new train was used as nothing older is built to run at full line speed, and it will presumably be converted back again. I imagine routine track geometry tests will be done with a "normal" test train, as it does not need full speed to do that out of hours.
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« Last Edit: November 19, 2015, 19:22:12 by stuving »
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Tim
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« Reply #82 on: November 16, 2015, 17:07:46 » |
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It is known These test trains have been running 10% over speed limits with safety equipment off so as it is possible to run at limit plus 10%. The speed at derailment is not confirmed, but the speed limit at location is 160 kph, so plus 10% 176kph. This was around about the 200th test, and all the previous tests ran successfully at the plus 10%.
The train involved was the French version of our NMT train, what kind of staffing does the NMT run with?
The 5 still missing in the above report the BBC» are now saying are accounted for and weren't actually on the train, but others may have been due to the "extra guests".
Thanks for the extra info. Presumably, TGVs▸ in normal use have an automatic system to prevent the train going faster than the permitted line speed. Presumably also, when you do the 10% overspeed test you disable or override that automatic system (or you do it on track before the lineside part of that system is working) . Presumably, that then allows for human error to result in you exceeding the linespeed by more than 10%.
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stuving
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« Reply #83 on: November 16, 2015, 17:13:24 » |
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Thanks for the extra info. Presumably, TGVs▸ in normal use have an automatic system to prevent the train going faster than the permitted line speed. Presumably also, when you do the 10% overspeed test you disable or override that automatic system (or you do it on track before the lineside part of that system is working) . Presumably, that then allows for human error to result in you exceeding the linespeed by more than 10%.
There's several things there we don't know - obviously you can allow a defined overspeed in several ways, only one of which is to not engage either of the safety control systems fitted. The driver survived and has been interviewed, and says he was sticking to the 176 km/hr testing speed limit. But remember, "only" 176 km/hr is still 110 mi/hr, easily enough to smash a train to pieces.
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LiskeardRich
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« Reply #84 on: November 16, 2015, 17:27:29 » |
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Grayrigg was about 100 mph for a comparison as to a modern train derailment in Britain under similar speeds.
The TGV▸ was running wrong line, Looking on maps and images of the location, the wrong line looks to have a sharper curve than the normal line. The classic and high speed lines run opposite sides, and the location of crash was where two single lines fly over each other from the high speed line to swap onto the classic line to normally get to the opposite side.
The driver has been interviewed and claimed he was sticking to the limits set of 176kph.
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All posts are my own personal believes, opinions and understandings!
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stuving
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« Reply #85 on: November 16, 2015, 17:34:58 » |
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One report I saw said this was the first run on this line in this direction at speed, though I can't see why that would be so important.
SNCF▸ have been saying they can't confirm the actual speed as the gendarmes have the data recorders under lock and key as evidence. I still don't understand why one of the signalling systems wasn't tracking the train, even if it was not enforcing speed limits. The test phase is supposed to test the signalling too.
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stuving
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« Reply #86 on: November 17, 2015, 09:04:57 » |
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BEA-TT published their final report on this accident in September. It didn't get much reported, as it doesn't really change anything in the interim report, so I for one missed it at the time. BEA-TT have a page of brief summaries of their reports in English, but have not added any new ones for several years. In this case RAIB▸ have put a summary in English on line. This emphasises the caveat that investigations for the prosecutor's office are proceeding, and were not all made available for this report. However, there is no obvious sign of a shortage of information, so that is perhaps just the formal position. The story line of how the accident happened is still that a cracked frog on a double slip led to the bolts on a fishplate failing one at a time, until it was free to flip up under a train and jam in a flangeway. This chain of events is reconstructed in great detail by reference to the marks and indentation on the wheels and bogie components. While that might not seem entirely necessary, it was important to make sure that no other cause, even a minor one, contributed to the derailment. The rest of the report looks at the inspection and measurement (by "Mauzin" trains) of this track, whether the faults were detected, and if so why they were not fixed. A lot of this sounds very familiar. A couple of things are missing from the report. One is a clear statement of the impact of the restructuring of SNCF▸ and RFF into a single organisation, which happened betwen the accident and this report. This should be slight, as SNCF did all the actual maintenance work anyway, but surely worth recording. The other is about what led to the 1500V DC▸ power being turned off, and whether that was a fault current due to the accident, and if damaged live wires constituted a danger. This was raised by comments elsewhere, before being commented on in this forum, but is not mentioned in the report. Presumably it was not in fact an issue at all.
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TonyK
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The artist formerly known as Four Track, Now!
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« Reply #87 on: November 17, 2015, 19:54:08 » |
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Advance news (in French) on RTL of the results of the enquiries. The first report is due out tomorrow - I think that's the interim technical report from the BEA-TT. RTL concentrate more on the (leaked) prosecutors' report, which seems to be heading for a criminal prosecution as well as a civil liability case. The news item talks about missing bolts in fishplates that no-one is bothered about, and maintenance that was both random and not thorough enough. The other theme, which is obviously going to have political implications, is the confused relationship between RFF and SNCF▸ , and how this clouds the responsibility for maintenance standards. All sounds rather familiar, doesn't it?
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Now, please!
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stuving
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« Reply #88 on: November 18, 2015, 17:13:32 » |
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We were half-promised a first statement of facts from SNCF▸ today, but examining the recorders only started this afternoon, so this first statement is now due tomorrow. I'm sure they will also have examined the track. If you want a wider view of the site and the track, SNCF have made several videos of overflights of the " LGV▸ Est European" while it was being built; there are links in this page. The earlier ones give a good impression of how much activity, machinery etc. it takes to build the whole line and its structures pretty well at once. The 2013 one even shows the TBM just emerged from the second bore of the Saverne tunnel. The latest, which was done last month and so is this the most relevant, is here. It flies West-East, so the Vendenheim junction is at the end (and the helicopter was overtaken by the test train, wrong road again, 2 minutes in). Saturday's run was on the right-hand track and derailed just before the canal bridge.
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stuving
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« Reply #89 on: November 19, 2015, 14:30:31 » |
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We now have that statement from SNCF▸ - and it's quite clear what the cause was: excessive speed. At the point of derailment, the recorded speed was 243 km/hr as against a normal limit of 160 km/hr. For this run, that is described as late braking; 1 km too late. (More later, when I get home.)
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