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Post by afarlie on Jun 22, 2009 23:06:19 GMT
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mrfs42
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Post by mrfs42 on Jun 22, 2009 23:21:09 GMT
Not nice - looks like a head-on smash.
Sympathies for the family of the Driver and the other person killed.
I know it is an ATO line, but I wonder what exactly was going on - some form of Single Line Working? The telescoping [1] doesn't look like a rear-end collision. Doubtless we'll find out in the fullness of time?
[1] in another railway accident led to my birth. However, that is a tale for another time and place.
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Deleted
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Post by Deleted on Jun 22, 2009 23:46:39 GMT
Quite alarming, looking on Wikipedia (yes, I know), how many accidents seem to occur on this system. In the time since the Leyton and Kilburn accidents Washington has had a number of serious and fatal collisions, but the network is rather smaller than LU.
Speculation made that in this accident the first train had derailed and the second collided with it.
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Phil
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Post by Phil on Jun 23, 2009 6:49:00 GMT
Is is a BBC thing or an American thing that mkes the report refer to a female driver? Over here we've long since stopped doing that sort of thing.......................
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mrfs42
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Post by mrfs42 on Jun 23, 2009 6:54:03 GMT
American; within the rail industry non-male drivers are a rarity.
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Post by pakenhamtrain on Jun 23, 2009 7:16:56 GMT
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Post by Deleted on Jun 23, 2009 12:41:40 GMT
Ouch! Makes you appreciate the tremendous safety record of the London Underground. Condolences for the friends and families.
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mrfs42
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Post by mrfs42 on Jun 23, 2009 13:27:47 GMT
Hmm. GRS relays. Hmm.
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Post by Deleted on Jun 23, 2009 14:22:32 GMT
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Post by kewgardensteleport on Jun 23, 2009 14:41:17 GMT
Is is a BBC thing or an American thing that mkes the report refer to a female driver? Over here we've long since stopped doing that sort of thing....................... At least they didn't call her a motorwoman. But I do have a strange sense of déjà vu here. Wasn't there a very similar accident on the Washington Metro a couple of years ago?
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towerman
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Post by towerman on Jun 23, 2009 20:19:41 GMT
Could cause problems over here if it was a TBTC system,cue a few heart attacks at Tubelines.
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Post by happybunny on Jun 23, 2009 20:24:31 GMT
I would say this :
"But four years ago, in an episode eerily similar to yesterday's, the signal system briefly failed in the tunnel between Foggy Bottom and Rosslyn, forcing two quick-thinking operators to stop their trains manually to avoid a crash.
In the June 2005 incident, the operator of one train noticed that he was getting too close to the train ahead. The signal system was telling him the track was clear, but he hit the brakes. The operator of a third train on the line hit the emergency brakes on time, too."
Is very very worrying as it sounds similar to the system going in on the Jubilee!
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prjb
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Post by prjb on Jun 23, 2009 22:09:28 GMT
Easy there everyone! Lets wait and see the outcome of the investigation, and bear in mind that any subsequent recommendations will be taken on board by signalling manufacturers and rail operators alike around the world. Additionally, I am not sure that the system on the Jubilee is the same in any case. The 'ORR' will no doubt take an interest too.
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mrfs42
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Post by mrfs42 on Jun 24, 2009 7:26:47 GMT
If anyone is interested: previous accident report from the Washington metro. Makes salient (and slightly worrying) reading: the fundamental problem was that during the construction of the metro, it was specified that the signalling system could assume a minimum braking performance of 1.65 m/s -2 at 75 mph, but the braking system of the cars was specified at a minimum braking performance of 0.88 m/s -2. Under low adhesion conditions, the trains could not stop within the signal blocks. I'm not suggesting for one moment that this has happened (for a start it wasn't snowing). The differences between the design speed and the actual speed were covered by a limiter, holding the train at 59mph rather than 75mph - if a train overran a block section the limiter would be reset to 75mph - which is what caused the previous accident as the train overran a platform in the snow. Makes for quite absorbing stuff; especially given the possiblilties of relays sticking: warning notices have been issued for GRS relays. The ATP/ATO is quite different to that for the Jubilee: Level 3. Balise underneath the first car in a platform: this was the headway control - and used to enforce the 59mph restriction. Non-vital. Level 2: Balise on the approach to the stations. This is the position reference for the braking profile. Non vital. Level 1: Audio frequency cab signalling system. Vital.
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Post by Deleted on Jun 24, 2009 9:42:47 GMT
Extremely disturbing what Trains [1] NewsWire has reported: Emerging crash details point to haywire control system
Published: Tuesday, June 23, 2009 WASHINGTON - The computerized control system that runs Metro's subway trains put the train into motion that slammed into the train ahead of it, according to the National Transportation Safety Board. The train's operator applied the emergency brake and discoloration of the brake rotors confirm the brakes engaged, but the train didn't stop; records reveal the train was two months past due for brake servicing. Work was done on the train control system earlier this month, however, between Fort Totten and the New Hampshire Street overpass.
Three subway trains were in the block at the time of the crash, which killed nine people. Earlier today, officials rolled the number of people killed to seven, but tonight's news conference confirmed the final death toll at nine. The train contained no event recorder and the operator was killed, limiting investigators' sources of information.
The Alstom train control system in place operates trains automatically, leaving the operator to oversee the train and activate the doors at stops. Why the system put the train in motion is unclear.
The train's operator had been running trains since March.
TRAINS News Wire will release more details as they become available. [1] American railfan magazine (is available in UK, website www.trains.com)
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Post by londonse on Jun 24, 2009 10:32:54 GMT
If anyone is interested: previous accident report from the Washington metro. Makes salient (and slightly worrying) reading: the fundamental problem was that during the construction of the metro, it was specified that the signalling system could assume a minimum braking performance of 1.65 m/s -2 at 75 mph, but the braking system of the cars was specified at a minimum braking performance of 0.88 m/s -2. Under low adhesion conditions, the trains could not stop within the signal blocks. I'm not suggesting for one moment that this has happened (for a start it wasn't snowing). The differences between the design speed and the actual speed were covered by a limiter, holding the train at 59mph rather than 75mph - if a train overran a block section the limiter would be reset to 75mph - which is what caused the previous accident as the train overran a platform in the snow. Makes for quite absorbing stuff; especially given the possiblilties of relays sticking: warning notices have been issued for GRS relays. The ATP/ATO is quite different to that for the Jubilee: Level 3. Balise underneath the first car in a platform: this was the headway control - and used to enforce the 59mph restriction. Non-vital. Level 2: Balise on the approach to the stations. This is the position reference for the braking profile. Non vital. Level 1: Audio frequency cab signalling system. Vital. There was an even more recent crash Nov 2004 auto section in tunnel, in all the reports I have read for Washington T/Op seems to be fairly new to job. It must be said that that all qualified to standard required.
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Post by Deleted on Jun 24, 2009 14:50:51 GMT
I would say that the most concerning thing is that after a similar but non-fatal crash on the Washington system, the National Transportation Safty Board (similar in scope to the RAIB) recommended that the cars of the series in yesterday's crash be retrofitted to (1) prevent the type of telescoping that occurred and (2) have their electronics upgraded. The cars are 30 years old and the politicians would not give Metro the money needed to either retrofit or buy new equoipment.
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Post by singaporesam on Jun 25, 2009 23:33:46 GMT
Its easy to blame the trains for the severity of the incident , but the fact remains the trains shouldn´t have collided. By giving excessive ´air time´ to the telescoping issue (in terms of no. pages in the report) the investigator has deflected attention away from the much more fundamental problem with the signaling system. The same goes for the trains are too old arguement. WMATA currently are procuring new trains (spec is available on their website) to replace the 1000 series cars, so there is a real risk that if this investigation focuses on the cars that WMATA will claim to be fixing the problem. The issues are the signaling and the safety management, also on the web there are couple of FTA reports giving WMATA a hard time over safety management
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Post by Deleted on Jul 6, 2009 16:15:09 GMT
I find this incident quite disturbing. This is only the second fatal accident caused by a train being driven in ATO. The first fatal ATO accident also took place on Washington Metrorail (and was partially caused by operator error). Washington Metrorail has a terrible safety record, with a few other accidents that have occured whilst trains were being manually driven.
The second report is below:-
SECOND UPDATE ON NTSB INVESTIGATION INTO COLLISION OF TWO METRORAIL TRAINS IN WASHINGTON, D.C.
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In its continuing investigation of the June 22, 2009, accident involving the collision of two Washington Metropolitan Area Transit Authority (WMATA) trains on the Red Line in Washington, D.C., the National Transportation Safety Board has developed the following factual information:
The examination of factors leading up to the accident continues. Investigators have been conducting nightly tests of the train control system at the accident site. Test progress was delayed by some water in underground access areas that made it unsafe for technicians to work on electrical cables until the water could be pumped out. The components being tested include track impedence bonds, wayside cables, and train control system circuitry for the track segment between the Fort Totten and Takoma stations.
As previously reported, initial testing showed that when the test train was stopped at the same location as the train that was struck in the accident, the train control system lost detection of the test train. Additionally, in subsequent testing over the weekend the train detection system intermittently failed; data is currently being collected to further analyze each component in the train detection system. Investigators are reviewing recorded track circuit data for each test configuration.
Maintenance records show that an impedence bond for the track circuit where the accident occurred was replaced on June 17th, five days before the accident. After a post- accident review of recorded track circuit data, WMATA reported to the NTSB that the track circuit periodically lost its ability to detect trains after June 17th; the NTSB is reviewing documentation on the performance of that track circuit both before and after the June 17th replacement.
The weekend of July 18th investigators intend to conduct sight distance tests using trains consisting of similar cars to those involved in the accident. The tests will establish when the struck train would have been visible from the striking train. The previously reported rail streak marks consistent with heavy braking were approximately 125 feet long, and began approximately 425 feet prior to the point of collision.
The investigative groups have concluded the on-scene phase of the investigation except for the Signals Group that continues to examine the train control system both at the scene of the accident and at the WMATA Operations Control Center.
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It seems that the track circuits failed to detect the stopped train, resulting in the signalling system thinking that the track ahead was clear. It should be noted that Washington Metrorail has a rather old ATO/ATP system, which is very different to the communication based train control (CBTC) systems that are installed on newer ATO installations.
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Post by Dstock7080 on Jul 6, 2009 17:37:52 GMT
Amazingly they are still running passenger trains over this section despite the continuing testing:
dated 6 July: "Unexpected Service Disruptions: Red Line trains remained restricted to a maximum speed of 35 mph, and trains traveled even slower between Fort Totten and Takoma Metrorail stations, as the investigation into the June 22 fatal train accident continued. Red Line customers experienced delays throughout the day and were encouraged to add at least 30 minutes to their travel time."
It looks as if the whole system is operating in ATP since 3 July:
"Starting Friday, July 3, at 7 a.m., trains will return to regular speeds on the Red Line except for those passing through the area of last week’s accident between Takoma and Fort Totten Metrorail stations. The Takoma Metrorail station will remain open Friday, July 3, and Saturday, July 4.
If trains get backed up, it is possible that some may be offloaded to turn trains around. This maneuver will allow Metro to get some trains to Glenmont, which in turn can provide more service for people traveling from Glenmont or Silver Spring into downtown Washington.
Metro will operate additional eight-car trains to carry more passengers throughout the holiday in an attempt to alleviate crowded conditions.
In addition, all trains on all color lines will be pulling to the front end of all platforms, so riders should check the passenger display signs located both on the platform and at the mezzanine level to determine where they should stand as they wait to board a train. Eight-car trains will fill the entire platform. However, customers will notice that when six-car trains pull into a station that there will be about 150 feet of empty platform space behind the train, so when the signs indicate that a six-car train is pulling into a station, customers should move toward the center or front of the platform for easy boarding."
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Colin
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Post by Colin on Jul 6, 2009 18:54:04 GMT
It should be noted that Washington Metrorail has a rather old ATO/ATP system, which is very different to the communication based train control (CBTC) systems that are installed on newer ATO installations. However, how old is it and (depending on the answer) how does it compare with the Victoria line's system? Eight-car trains will fill the entire platform. However, customers will notice that when six-car trains pull into a station that there will be about 150 feet of empty platform space behind the train Their cars are 75' foot long? Seriously???
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Post by norbitonflyer on Jul 6, 2009 19:02:36 GMT
Their cars are 75' foot long? Seriously??? That's just under 23 metres - the same as a MkIII coach or a Class 156
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mrfs42
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Post by mrfs42 on Jul 6, 2009 22:01:59 GMT
However, how old is it and (depending on the answer) how does it compare with the Victoria line's system? Opened 5 years after the Brixtion extension. The major difference is that the system (WMATA) is controlled by a central computer; there is system wide oversight. As such there isn't on the Vic - just a reporting capability to/from local IMRs and Cobourg. AIUI speed codes are issued from the main computer, rather than the code being generated locally at the IMR. WMATA is a lot more solid-state with little mysterious boxes connected by cable rather than the Vic (which for an all-too-short time will be predominantly electromechanical - with understandable and tangible components). Eight-car trains will fill the entire platform. However, customers will notice that when six-car trains pull into a station that there will be about 150 feet of empty platform space behind the train Their cars are 75' foot long? Seriously??? Yup - you know what they say about everything being bigger over there.
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Post by singaporesam on Jul 7, 2009 23:21:05 GMT
Their cars are 75' foot long? Seriously??? That's just under 23 metres - the same as a MkIII coach or a Class 156 Actually around 23 metres and a width of between 3m and 3.2m is pretty much the standard size for modern metros . These are the dimensions of a Chinese type A car , Hong Kong , Singapore , Taipei etc.
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Post by Deleted on Jul 8, 2009 7:38:35 GMT
"In addition, all trains on all color lines will be pulling to the front end of all platforms" I think this is so that the the trains comminicate with the Washington equivalent of the PAC. The previous Washington in-ATO crash was caused by a train overrunning the PAC due to icy conditions, defaulting to highest performance due to lack of comminication with the PAC, and then (not surprisingly) overrunning the next station and hitting a train in the overrun tracks. After that incident, why did WMATA not change their policy for all trains to have to line up with the PAC at all stations? If this does not occur the train should be run in manual at slower speeds. WMATAs operating policies just don't seem right!
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Post by compsci on Jul 8, 2009 8:52:54 GMT
Defaulting to highest performance in the event that the train doesn't receive instructions to the contary seems particularly odd. I would have thought that the ATO system shutting down completely (if necessary bringing the train to a stop first) would be safest.
It appears likely that the highest performance setting is represented by 0 internally, and, since most variables in computer systems are start set to 0 at start up (note that the system appears to be shut down when the doors are opened), if no attempt is made to change the setting, or to notice that there has been no such change, you'll end up with the highest performance setting being selected.
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Post by pakenhamtrain on Jul 9, 2009 11:08:07 GMT
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Post by Deleted on Nov 10, 2009 16:28:34 GMT
Apologies for reraising this, but some thing I have just come across - from a different, if sobering, viewpoint: - but not one which should be overlooked.
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Post by singaporesam on Nov 11, 2009 12:45:19 GMT
Actually re-raising is quite timely . It seems that Metro are exploiting this accident to seek extra funding www.wmata.com/about_metro/june22.cfmThe trouble is that their problems are useless Safety Management practices as the previous incidents have shown.
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Post by singaporesam on Nov 11, 2009 12:52:01 GMT
They´ve even put up a the track circuits turned off but we can still see the train video on You Tube !
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