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Fri Aug 2nd, 2013 at 09:56:14 PM EST
Shocking numbers from Santiago de Compostela in Spain continue to mount as the hours go by: Over 60 dead and 100-odd injured as train derails in Santiago
The accident took place near 21h barely 2km from the Santiago station, at the junction of A Grandeira. Renfe confirms that an investigation has been opened to determine the causes of the accident, and it's not et confirming that it was caused by excess speed, the hypothesis considered so far.
Update [2013-7-30 4:19:46 by Migeru]:
As told by passengers and witnesses of the accident, the train derailed at the curve of A Grandeira -limited to 80km/h- and one of the cars overturned, the rest derailed, and some of them burst into flames.
It appears that the driver has admitted he was "distracted" and was not aware he was going into the last tunnel before Santiago, where he needed to be braking the train from 200km/h down to 80km/h. The ERTMS safety system, which is necessary for safety above 200km/h and can prevent the train from exceeding the speed limit and cannot be overridden by the driver, was by design
not installed in the last 7km of the 87-km stretch to Santiago, presumably because the train is supposed to go below 200 on the entire 7-km stretch and ERTMS was seen as "overkill". But this left the line only with the ASFA security system, which can signal to the driver that he's going above the speed limit but requires driver input to slow down the train. Moreover, the last 7km of track before Santiago and in the tunnel just before the curve where the crash took place have a low number of ASFA beacons installed, and they appear to be the older-spec "analog ASFA" and not the newer "digital ASFA". Digital ASFA is used as backup for ERTMS throughout Spain's high-speed network because it can operate at speeds above 200km/h. It also appears the Alvia train hasn't been certified to use ERTMS and/or the ERTMS wasn't fully operational on the day of the crash.
In sum, it looks like there was a combination of four factors (sources below the fold):
- the driver had a distraction. At 200km/h it takes 70-90 seconds to traverse the 4-5 km on which the train is supposed to slow down to 80km/h. The driver braked too late if at all.
- the Alvia train was not an AVE, it is halfway up from a conventional train, upgraded to run on high-speed track. It is possible that the on-board speed safety system was not certified to use ERMTS because its top speed is lower than regular AVE.
- the installed speed safety system on the last 7km of track was done on the cheap, going for fewer analog ASFA beacons as opposed to digital ASFA.
- the design of the speed safety system was not fail-safe: excluding ERTMS from the last 7km of track implies the assumption that the train will never enter that stretch above 200km/h.
This looks to be one of Europe's worst rail accidents. Use this as an open thread.
Update [2013-8-2 21:56:14 by Migeru]:
- RTVE: The driver of the train wrecked in Santiago is freed with charges after admitting negligence (28.07.2013)
- Vozpópuli: Alvia: fake high speed with a conventional train's speed control and signalling system (26-07-2013)
El País: What is the safety system of the Alvia Madrid-Ferrol? (26 July 2013)
Up to Olmedo (Valladolid) the ERTMS system is active. From then on, ASFA is working. There is an 80km stretch between Ourense and Santiago where ERTMS is deployed. However, RENFE has not certified the system for the Alvia in that section, as confirmed by ADIF desite the fact that Avant middle-distance trains on the sameline do use it. RENFE, asked by this paper, did not clarify why 13 months after hybrid Alvia started rolling there they still don't have that safety. They also did not confirm whether the system is operational on the Avant trains. In any case, and desite the fact that the Alvia would be able to reach 220km/h in parts of the Ourense-Santiago section, it cannot do it because it is monitored by ASFA: the speed limit for any train controlled by that system is 200.
- El Diario: The section of the Santiago wreckage has the analog security system from a half-century ago (27/07/2013)
Público: Fomento asume que tres balizas habrían evitado el accidente del Alvia
(2 August 2013)
Técnicos ferroviarios ya señalaron a Público que con una baliza se habría evitado el accidente. Y Adif, que enseguida culpabilizó al maquinista, se ha apresurado a instalar nuevas balizas en el fatídico tramo durante toda esta semana. Así, "en el punto kilométrico 81/669 Adif instaló el lunes una baliza y un cartelón que limitan la velocidad a 30 km/hora", confirma el comunicado de Fomento. Esta señal está protegida por otra anterior que limita la velocidad a 60 km/hora y, ayer mismo, los responsables de la infraestructura férrea colocaron otra nueva baliza, con su correspondiente "cartelón" a 160 km/hora.
El ASFA Digital, el sistema que ha reforzado Adif esta semana, consiste en un equipo de señalización que, a través de las balizas de aviso y preaviso situadas en las vías del tren, informan al maquinista de la peligrosidad del trazado que se va a encontrar en los kilómetros siguientes. Si el siguiente semáforo está en verde, el conductor del tren tiene vía libre para continuar a la misma velocidad. Si, por el contrario, está en amarillo, la baliza de preaviso emite una señal al tren para que reduzca la velocidad. El conductor debe entonces comunicar que ha recibido el aviso y, al tiempo, frenar para disminuir la velocidad. Si el maquinista no se entera de dicha señal, el siguiente semáforo se pondría en rojo, las balizas de la vía emitirían la señal de peligro al tren y, automáticamente, la máquina se pararía.
Por ello, "la limitación de velocidad de 80 Km/h estipulada para la curva del accidente se podría haber protegido sin necesidad de ERTMS[ European Rail Traffic Managemegent System, el sistema europeo (y moderno) de seguridad ferroviaria]. Habiendo hecho otra configuración de las señales convencionales, el ASFA habría protegido el exceso de velocidad en la curva", señalaron expertos del sector a este diario.
Público: The ministry of public works accepts that three beacons would have prevented the Alvia crash
(2 August 2013)
Railroad technicians already pointed out to Público that a single beacon would have prevented the accident. And Adif, which immediately blamed the driver, has hurried to install new beacons in the fateful stretch diring this week. Thus, "at kilometer 81/669 Adif installed Monday one beacon and sign limiting speed to 30km/h", confirms the release from the ministry. This signal is protected by an earlier one limiting speed to 60 km/h and, just yesterday, the rail infrastructure authorities intalled a new beacon, with its associated "placard" at 160 km/h.
Digital ASFA, the system that Adif reinforced this week, consists of a signalling system which, by means of warning and pre-warning beacons, placed on the track, will imform the driver of the danger in the line he will encounter in the following kilometres. If the following light is green, the driver is free to continue at the same speed. if it is yellow, the pre-warning beacon emits a sends a signal to the train to reduce its speed. The driver muct communicate that he has received the warning and, at the same time, brake to slow down. If the driver misses the signal the next light will be set red, track beacons will emit a danger signal, and the engine will stop automaticaly.
Thus, "the 80 Km/h speed limit stipulated for the accident curve could have been protected without ERTMS[ European Rail Traffic Managemegent System, the (modern) European rail safety system]. With a different configuration of conventional ignals, the ASFA could have protected the speed excess on the curve", sector experts told this paper.
Better late than never. Now we'll see what the outcome of the court case is. The driver shouldn't be assigned full responsibility for the crash.
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