Spanish investigators are considering whether a railway signalling system failure could have contributed to a catastrophic train crash that killed 79 people late last month.
The Alvia intercity train was travelling between Madrid and Ferrol on the north west coast when it derailed at 8.41pm local time as it approached the station at Santiago de Compostela.
Investigators said the eight car passenger train was travelling at 192km/h, more than twice the 80km/h speed limit as it travelled along a bend 4km from the station.
A video posted online appears to show the moment the train came off the track. The distressing video comes from a trackside camera that is understood to belong to Spain’s national rail company.
The accident occurred on a section of the track at the interface between where two rail safety systems. One is the high tech, European Rail Traffic Management System (ERTMS) and the other is Spain’s ASFA system, which is used on lower speed sections of the Spanish network. ERTMS forces trains to brake if they are travelling above predefined safety speeds.
The train, which was operated by rail company Renfe was understood to be fitted with level one ERTMS equipment.
The section of track where the crash occurred is owned and maintained by track operator Adif. This had the lower-spec ASFA system. ASFA only applies the brakes on trains travelling more than 200km/h.
A Network Rail spokesman said a similar crash in the UK was extremely unlikely because while ERMTS is being phased in, the UK Train Protection Warning System (TPWS – see box) currently in use will remain in operation. “In the UK, if the speed limit drops by a third, say from 125 miles per hour to 80mph and the driver hasn’t already slowed down, the TPWS will stop the train automatically,” he said.
European Rail Traffice Management System
The European Rail Traffic Management System (ERTMS) has been developed in an attempt to standardise rail safety systems across Europe. It controls the speed of trains without the use of trackside signals.
Eight firms developed the system – Alstom Transport, Ansaldo STS, AZD Praha, Bombardier Transportation, Invensys Rail, Mermec, Siemens Mobility and Thales.
It comprises two systems: The European Train Control System (ETCS) and the Global System for Mobile Communications – Railway (GSM-R) mobile communications systems.
There are three levels of ERTMS: Level 1 is an add-on designed for conventional lines already equipped with trackside signals and train detectors with the ETCS determining when and where an on board computer brakes the train; Level 2 does not require trackside signals and uses ETCS and GSM-R to allow the train to reach its optimum or maximum speed while maintaining a safe braking distance; Level 3 is conceptual and uses equipment within the train to continuously supply data on the train’s position to the control centre, rather than trackside equipment.