In the minutes following the test train accident which took place on Saturday 14 November at Eckwersheim on the new Est Européenne line, the managing director of the Railway Safety System launched, at the request of the SNCF management team, an immediate investigation via the SNCF Audits and Safety directorate general. Investigators from the Audits and Safety directorate general went to the accident site in order to gather and understand the initial findings of the accident. The internal report on the immediate investigation was submitted to the Chairmen on Thursday 19 November.
Background to the accident
The accident took place outside the operational national rail network, as running on this line section is managed by those in charge of testing. The tests are intended to analyse and gain experience of the properties of the new line, and include running at speeds up to 10% greater than commercial speeds. To do this, the some automated speed control systems on board the test train are disabled as part of the test protocol and are instead controlled by a team of experts. This is not the case for commercial services running on the operational national rail network.
This test train run was performed as part of dynamic testing to study the properties of the line before it was approved. For information, its scheduled commercial opening was the 3 April 2016.
All of the components of the line’s sub-systems had already been verified. Since 28 September almost 200 technical test runs had been carried out on this future new line (cf “Temps Réel”, issue No. 77). This was to be the final run of the dynamic testing phase. The test train was fitted with measuring equipment and composed of two power cars and eight coaches. 53 people were on board: SNCF Group engineers and technicians, and their companions. There were 7 people in the driving cab.
The facts at the time of the accident
The test train left the Meuse TGV station at 14:18 and in accordance with the test protocol, gradually increased speed on the line to reach 352 km/h, 10% above the maximum commercial speed of 320 km/h. It then began a deceleration phase once it reached Vendenheim, as this is where the connection to the conventional line is located, allowing access to Strasbourg.
Immediate cause of the accident
After examining the black boxes (Atess recording tapes), the investigators established that the speed of the test train as it entered the section was greater than the speed assigned for the test run. The assigned operating speed was 176 km/h and the speed recorded was 265 km/h. The accident took place at a speed of 243 km/h.
This increased speed was due to a late braking sequence of the test train.
As a result of the centrifugal force exerted, the lead power car derailed and came to rest on the embankment. All the other investigations of the internal investigators have confirmed that no abnormalities were found with regard to the infrastructure of the line or the rolling stock. In addition, there were no abnormalities in terms of the traffic management of the test train.
Continuation of the interval investigations
It is too early to know the causes of this late braking sequence. Investigations will continue, focusing on procedures and human error.