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| Amtrak (US) crash 13/05/2015 at 04:07 #72140 | |
GeoffM
6285 posts |
All the major news outlets are carrying the story so I won't bother with links. Currently "at least 5 dead" and "6 critical", 243 on board, all seven carriages derailed, engine separated. Just north of Philadelphia on the North East Corridor. No obvious cause but plenty of speculation of course.
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| Amtrak (US) crash 13/05/2015 at 11:09 #72147 | |
Jersey_Mike
250 posts |
Not sure what happened, but the accident occurred on a 50mph curve at the end of a 70mph segment. Unless the engineer accelerated (which is always possible), entering the curve at 70mph should not have lead to a derailment. The opposite direction where 125mph track leads into the 50 mph curve is protected by a cab signal drop.
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| Amtrak (US) crash 13/05/2015 at 18:54 #72152 | |
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TylerE
149 posts |
Reports are now saying the train was travelling at approx. 107mph.
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| Amtrak (US) crash 14/05/2015 at 01:38 #72157 | |
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Jersey_Mike
250 posts |
" said:Reports are now saying the train was travelling at approx. 107mph.I'm not surprised. The route in question traveling in the eastbound sees an 80mph stretch with a 65mph curve to the right, then the 50/60mph sharp curve to the left followed immediately by a softer curve to the right again before straightening out onto a 110mph section. To someone not paying attention the first curve could feel like the second, making them think it is time to open the throttle. Still, the physical characteristics are very distinct heading into the sharp curve including big yellow 50mph signs in the catenary and an interlocking plant. I found it hard to believe that even after accelerating to 110, the engineer would have not made some effort to remedy his mistake before derailing. Like I said this is not the typical case of a train traveling at high speed failing to slow down. The train was traveling at 70-80mph and then accelerated to 110. Log in to reply |
| Amtrak (US) crash 14/05/2015 at 01:48 #72158 | |
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GeoffM
6285 posts |
" said:I found it hard to believe that even after accelerating to 110, the engineer would have not made some effort to remedy his mistake before derailing.He did, according to the NTSB. Emergency brakes but only ~3mph reduction before the end of the data. Even Amtrak's own website (live train tracker thing) showed 106mph from a tweet I saw, assuming it wasn't faked. Elsewhere somebody said this section of track wasn't fitted with ACSES, but knowing what I know about ACSES, it may not have helped that much anyway, because it's not granular enough for short reductions in speed limits. To be fair, "remedy his mistake" is a little strong when we have no idea why the train was speeding. It reminds me of the subway train crashing at Chicago which undoubtedly was due to driver error - but when the evidence came out it showed the CTA somewhat complicit in effectively forcing a new hire to work a dangerous combination of shifts. SimSig Boss Last edited: 14/05/2015 at 01:52 by GeoffM Log in to reply |
| Amtrak (US) crash 14/05/2015 at 01:51 #72160 | |
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Muzer
718 posts |
Would this sort of incident be prevented in Britain? Would a stretch of track like that require TPWS fitment or would that not occur for these particular speeds? (Obviously we're assuming it's not on the West Coast Main Line, Chiltern Main Line, Great Western Main Line, HS1 or the Cambrian Coast Line, all of which have more sophisticated systems that I suspect probably WOULD prevent this, at least for compatible trains). (I don't mean this to pick on US rail safety, I'm just curious if the systems we have here would have been enough or not). Last edited: 14/05/2015 at 01:51 by Muzer Log in to reply |
| Amtrak (US) crash 14/05/2015 at 02:05 #72161 | |
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GeoffM
6285 posts |
" said:Would this sort of incident be prevented in Britain? Would a stretch of track like that require TPWS fitment or would that not occur for these particular speeds? (Obviously we're assuming it's not on the West Coast Main Line, Chiltern Main Line, Great Western Main Line, HS1 or the Cambrian Coast Line, all of which have more sophisticated systems that I suspect probably WOULD prevent this, at least for compatible trains).TPWS could have prevented an overspeed but I'm not sure the UK uses it that often for speed limits alone - and, if anything, would limit it at the start of the section, not continuously through it. ERTMS/PTC almost certainly would have prevented it. No worries picking on US rail safety. After all, you're only 58 times more likely to be injured on Amtrak than on SNCF apparently... SimSig Boss Log in to reply |
| Amtrak (US) crash 14/05/2015 at 03:19 #72162 | |
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Jersey_Mike
250 posts |
" said:A plethora of employees on a Facebook group have vouched for the person who was working a fairly typical shift pattern. A good friend of mine was actually driving the train following T188. Quote: Would this sort of incident be prevented in Britain? Would a stretch of track like that require TPWS fitment or would that not occur for these particular speeds? (Obviously we're assuming it's not on the West Coast Main Line, Chiltern Main Line, Great Western Main Line, HS1 or the Cambrian Coast Line, all of which have more sophisticated systems that I suspect probably WOULD prevent this, at least for compatible trains).This was not seen as a high risk curve for eastbound trains. Track speed before the curve was only 80mph eastbound. The most common error is inattention, but a train making no speed reduction from 80mph would not derail on the curve. Westbound trains get a cab signal drop as that is a 110mph to 50mph drop and as you see, will result in a derailment. Also 50mph is for passenger comfort. Tilting trainsets can negotiate the curve at 60mph. Last edited: 14/05/2015 at 03:20 by Jersey_Mike Log in to reply |
| Amtrak (US) crash 14/05/2015 at 08:17 #72166 | |
Steamer
3923 posts |
" said:" said:I'm fairly sure TPWS is installed at certain high-risk locations (Morpeth, for instance), but they're few and far between. It's also unlikely to have been installed in this instance, for the reasons given by Mike.Would this sort of incident be prevented in Britain? Would a stretch of track like that require TPWS fitment or would that not occur for these particular speeds? (Obviously we're assuming it's not on the West Coast Main Line, Chiltern Main Line, Great Western Main Line, HS1 or the Cambrian Coast Line, all of which have more sophisticated systems that I suspect probably WOULD prevent this, at least for compatible trains).TPWS could have prevented an overspeed but I'm not sure the UK uses it that often for speed limits alone - and, if anything, would limit it at the start of the section, not continuously through it. "Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Last edited: 14/05/2015 at 08:22 by Steamer Log in to reply |
| Amtrak (US) crash 14/05/2015 at 11:02 #72180 | |
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Firefly
521 posts |
TPWS fitment is only required where the speed on approach is greater than 60mph and the speed reduction is greater than one third. If there are multiple speed reductions in a 2 mile section of railway the worst case is considered. So with Mike's figures it's possible that it would have had TPWS fitted. 80mph reduction to 65mph - Not Required 65mph to 50mph - Not Required However if the reduction to 65mph was less than 2 miles from the 50mph restriction we consider it 80mph to 50mph and TPWS would be fitted. TPWS only checks your speed once on approach to the PSR, if a driver accelerates after the check point there will be nothing to stop a derailment. FF Log in to reply |
| Amtrak (US) crash 14/05/2015 at 11:55 #72181 | |
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Jersey_Mike
250 posts |
If the derailment took place on track 1 (which I believe was the case), speed of approach would have been 70mph. Anyway, shouldn't the risk be based on the overturn speed of the curve? Log in to reply |
| Amtrak (US) crash 14/05/2015 at 11:58 #72183 | |
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Muzer
718 posts |
Which is (usually) directly related to the speed limit, so it basically IS.
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| Amtrak (US) crash 14/05/2015 at 12:40 #72190 | |
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Jersey_Mike
250 posts |
" said:Which is (usually) directly related to the speed limit, so it basically IS.If the overturn speed is higher than the approach speed why would one need TPWS protection? Log in to reply |
| Amtrak (US) crash 14/05/2015 at 13:13 #72195 | |
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Steamer
3923 posts |
" said:" said:The rules appear to be defined so that TPWS is only provided where the approach speed is near, or over, the overturn speed.Which is (usually) directly related to the speed limit, so it basically IS.If the overturn speed is higher than the approach speed why would one need TPWS protection? As an example, the estimated overturn speed for Morpeth is 75mph, with a 50mph limit. Let's take the 25-30mph safety margin as standard. Firefly has said that it's only provided where the approach speed is over 60mph and the reduction is more than one-third. So, say a 40mph curve with 60mph approach. That's on the lower boundary of protection being provided, and using the assumption above the overturn speed is 65-70mph. That's pretty close to the approach speed, and any increases will take the approach speed closer to, or higher than, the overturn speed. "Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q) Last edited: 14/05/2015 at 13:14 by Steamer Log in to reply |
| Amtrak (US) crash 14/05/2015 at 13:20 #72196 | |
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Firefly
521 posts |
Speed limits are there for a reason. Usually overturn risk or track damage, sometimes signal spacing. Why wouldn't you provide TPWS for a significant speed restriction? Log in to reply |
| Amtrak (US) crash 14/05/2015 at 16:17 #72205 | |
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Jersey_Mike
250 posts |
" said:Speed limits are there for a reason. Usually overturn risk or track damage, sometimes signal spacing.It's something else to install and maintain for a limited gain in safety? Last edited: 14/05/2015 at 16:26 by Jersey_Mike Log in to reply |
| Amtrak (US) crash 14/05/2015 at 17:25 #72209 | |
KymriskaDraken
963 posts |
" said:Speed limits are there for a reason. Usually overturn risk or track damage, sometimes signal spacing.I shall just say one word: Morpeth. Kev Log in to reply |
| Amtrak (US) crash 14/05/2015 at 17:57 #72211 | |
jc92
3630 posts |
" said:" said:And Eltham Well Hall.Speed limits are there for a reason. Usually overturn risk or track damage, sometimes signal spacing.I shall just say one word: Morpeth. "We don't stop camborne wednesdays" Log in to reply |
| Amtrak (US) crash 14/05/2015 at 18:09 #72213 | |
postal
5190 posts |
" said:" said:Different attitudes to risks and different outcomes - see this article on the BBC web-site.Speed limits are there for a reason. Usually overturn risk or track damage, sometimes signal spacing.It's something else to install and maintain for a limited gain in safety? My personal take is that for about 10 years of my working life I was travelling 50,000 miles a year on the UK rail network. I was involved in two fatal incidents (both suicides) and was never injured. If the BBC article is soundly based I would have been injured 6 times during the course of my travelling had I been using the US network. Mike may find that a limited gain in safety, but to me it is quite a major consideration. “In life, there is always someone out there, who won’t like you, for whatever reason, don’t let the insecurities in their lives affect yours.” – Rashida Rowe Last edited: 14/05/2015 at 18:10 by postal Log in to reply |
| Amtrak (US) crash 14/05/2015 at 18:41 #72216 | |
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GeoffM
6285 posts |
" said:If the BBC article is soundly basedThis appears to be the article on which the BBC one is based. SimSig Boss Log in to reply |
| Amtrak (US) crash 14/05/2015 at 18:54 #72219 | |
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Jersey_Mike
250 posts |
BTW, I would like to point out what appears to be possibly the best head-to-head comparison of European and American style rolling stock in an accident. If you recall the Santiago de Compostela rail disaster... Quote: The Santiago de Compostela rail disaster occurred on 24 July 2013, when an Alvia high-speed train travelling from Madrid to Ferrol, in the north-west of Spain, derailed at high speed on a bend about 4 kilometres (2.5 mi) outside of the railway station at Santiago de Compostela, Spain. Of the 222 people (218 passengers and 4 crew) aboard, around 140 were injured and 79 died.[3]Almost the exact same situation rounding a 50mph curve at ~100 mph with 222 people on board (Amtrak Train 188 had 242 total passengers and crew). The results? Lightweight Talgo Stock = 79 dead Traditional Budd Company stock = 8 dead As far as I am concerned the system worked. This is Amtrak's first major accident on the NEC since 1986 and because of its choice of rolling stock only 8 people were killed instead of 79. When casualty rates are this low I'm saying it's sensible to make rail more affordable so people get off the drastically more dangerous roads. Of course if you do choose less robust equipment you'll need to spend more to keep them from running into things. Last edited: 14/05/2015 at 18:56 by Jersey_Mike Log in to reply |
| Amtrak (US) crash 14/05/2015 at 19:41 #72222 | |
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GeoffM
6285 posts |
Oh dear. Let's try some facts for size. The Spanish train stopped in about 50m, slamming against a solid concrete retaining wall. At a minimum the Amtrak train travelled at least double that distance on soft, bouncy earth. The forces involved varied massively between the two. :doh SimSig Boss Log in to reply |
| Amtrak (US) crash 14/05/2015 at 23:08 #72226 | |
bfcmik
98 posts |
Another major difference in the casualty rates were the different stages of the journey the Spanish and US trains were at. Yesterday's Amtrak 188 derailment took place not too long after leaving the station in Philadelphia so passengers would almost all have been seated whilst the Spanish crash occurred just 2.5 miles before the next station. Many people would have been standing and getting their possessions together, putting on street clothes or simply trying to make their way to the coach exits. As GeoffM says, other factors such as deceleration rates would have made a massive difference, and, since no 2 accidents have the same consequences, the positions that the passengers were travelling would have been different and thus the individual outcomes would not be equal e.g. someone travelling in seat 2a may not experience the same degree of trauma as a passenger seated at 14c in the same coach. Log in to reply |
| Amtrak (US) crash 15/05/2015 at 08:27 #72234 | |
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kbarber
1712 posts |
I'd suggest, like others, the difference between Santiago and this is what the train hit. Had there been a concrete retaining wall and bridge piers at the Philadelphia site I would expect a similar casualty toll to Santiago. Had there been a nice open space for the train to run in to at Santiago I'd expect a death toll similar to Philadelphia. Also worth noting, given the discussion of TPWS and approach speeds, that the train was running at 106mph although the authorised speed on the section approaching the curve was 70mph. TPWS would be set up for authorised speeds and would provide limited protection, I suspect, if approached at a speed something like 30% higher than the limit. Log in to reply |
| Amtrak (US) crash 15/05/2015 at 17:28 #72265 | |
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Jersey_Mike
250 posts |
" said:I'd suggest, like others, the difference between Santiago and this is what the train hit. Had there been a concrete retaining wall and bridge piers at the Philadelphia site I would expect a similar casualty toll to Santiago. Had there been a nice open space for the train to run in to at Santiago I'd expect a death toll similar to Philadelphia.In the Spanish wreck the train first broke apart in the middle sending crashing up an embankment. Here the ruggedized locomotive jumped the tracks first and acted as a ram to clear the way. I think the first coach, where all the fatalities were, got wrapped around one of the 1930's H-beam catenary supports, but the other coaches were intact and two didn't even leave the tracks. It's not a perfect comparison, but I'm impressed by the performance. A corrugated stainless steel body does make a difference. Log in to reply |