Published 30th July 2013
There has been much media attention on the dreadful Spanish train crash that occurred on July 24th in northern Spain. The various reports suggest that the train may have been exceeding the line’s speed limit by a considerable margin and being the key factor in the cause of the crash.
The 12 carriage train was the 1500hrs service between Madrid and Ferrol Alvia and it came off the tracks on a curve approaching the station at Santiago de Compostela. The train was a Class 730 with a dual gauge capacity train carryimng Spanish Railways said, 218 passengers. This means that it could operate over both track gauges used in Spain and was being operated by Spanish train operator RENFEusing tracks maintained by the Spanish ‚Network Rail‘ infrastructure company called ADIF.
The had an electric and a diesel power car at each end and it looks as though the rear one caught fire after the impact and this derailed carriages which hit a concrete lineside retaining wall.
The train had previously been running on the high speed track but was now on the ‚classic‘ line braking ready for the station stop a couple of miles away. The linespeed is reported as being 50mph on this curve and it has been suggested the train was travelling at more than twice this speed limit.
The Spanish high speed routes have been fitted with the European Rail Trafic Management System but other routes are yet to be fitted.
Track faults. Broken rail or fishplate jamming in a set of points as in France last week.
Signalling fault or error.
A train fault which may include wheel profile, axle problems or suspension issues.
Human error which seems to be suggested in this case if the speeding claims are found to be correct and possibly a factor in the recent Canadian train crash.
99% of times it is a combination of at least two of these plus contributory factors.
Rail.co.uk looks at how trains’ speeds are governed and looks at why accidents like this have been historically used to improve safety once the cause has been established.
There are a couple of phrases in the rail industry which can also apply elsewhere, these are ‘the price of safety’ or ‘the cost of safety. For those in the rail industry it is in cold terms, the calculation that drives safety investment. For example, if say £10million of investment can save a life, then the investment will go ahead.
This is standard planning in any transportation business, whether rail, coach, plane or in shipping. In essence, it articulates the huge cost of being unsafe can in both human and cash terms. When the RMT leader Bob Crow and his colleagues talk about safety being reduced because of funding cuts, it makes good scaremongering headlines but is not the reality of what goes on.
The railways run using complex systems on trains, on the track and signalling which must all be able to interface with each other all the time. These have been introduced in the UK in ever increasing amounts in the last 15 years or so and have proved their worth. Hundreds of millions of pounds have been invested since the Clapham crash 25 years ago improving safety.
The Clapham crash happened when three trains collided after a signal wire was wrongly installed and nearly 40 passengers were killed. One of the results of this was that the 1950s and 60s built ‘slam door’ trains involved had to be replaced by the end of 1999, a decade later. This was because they were not designed to be crashworthy and were prone to collapse in an accident.
Privatisation brought the introduction of the new trains and they had to go through an onerous safety approval process. The top railway safety board at this time was The Rolling Stock Acceptance Board and used technical experts to scrutinise the minutest of details to ensure all trains were safe to operate in passenger service.
This included right down to the design of seating and luggage racks to provide protection from luggage being dislodged inside the carriages in the event of a crash. Today’s carriages carry on the British Rail design using a monocoque strong steel shell combined with new designs of suspension and wheel profiles designed for maximum stability.
This is one of the reasons UK trains are safe today as they are resilient and built to withstand crashworthy. The Spanish carriages also showed considerable resilience in this crash but it seems that the speed of the train threw passengers around in the train, made worse possibly by them standing getting ready to get off the train at the nearby station.
The railways changed again after the 1990s dreadful accidents at Southall and Ladbroke Grove with the implementation of Train, Protection and Warning System (TPWS). This meant that the train’s speed was measured by a pair of track grids in advance of a signal and if the track speed was being exceeded, the brakes would be automatically applied bringing the train to a stop.
This system has reduced the chances of a collision to virtually zero and the same system will activate the brakes if a driver passes a signal at danger, known as a SPAD.
UK track is inspected and maintained to strict tolerances to ensure compatibility with train wheel profiles and we still use principles known as the Hallade principles of 1934 used when the LMS was testing trains at over 110mph. This included such things as transition curve profiles to allow tight curves to be negotiated at speed.
Today, we have tilting trains that do the same job and are based on lineside balises (transponders) that instruct the train to tilt up to 8 degrees depending on the radius of the curve.
The next signalling system being trialled in the UK is the European Rail Traffic Management System (ERTMS) also known as the European Train Control System, (ETCS). This system uses GPS to determine the location of the train and overlays it with the linespeed and again, if the train is going too fast for the supervisory system, the brakes are automatically applied until the train’s speed decreases to the permissible speed. This is being trialled on the Cambrian lines west of Shrewsbury at the moment with varying results.
We have the Rail Accident Investigation Branch who investigates all accidents and near misses and ascertain the root cause of the accident. It then makes recommendations designed to make sure the fault is not repeated. It is up to the Office of Rail Regulation to bring any criminal charges.
If indeed it is established that the cause was the driver speeding, then the reason why will be investigated. In the UK, the driver(s) would be drink and drug tested as a start. Then they would be interviewed to see if they had worked long shifts, had any family problems or any other worries that may have impaired their concentration.
And if the train was speeding, why didn’t the speed supervisory systems kick in and take charge as designed, reducing the speed and stopping the train preventing the accident.
When the railway system was being developed accidents happened, some minor and some causing huge loss of life. An early mishap with no injuries was after Wolverton Works designed a fast express locomotive to work between Euston and Birmingham in 1849. On its first outing to Euston, its outside bearings hit the platform edge. Because of this, the LNWR structural gauging process was established, a classic early example of learning from an accident.
Again at Wolverton, in 1882 The London North Western Railway diverted the fast main line railway away from the centre of Wolverton Works for safety reasons. It has run ever since through tight reverse curves safely so using fast trains round tight curves is not a safety issue if the railway systems and drivers combine as designed to keep to a safe speed.
These subjects are all looked at in Wolverton – The Full Works, a book to be published in September celebrating the 175th anniversary of the Works, the world’s longest operating railway works.
Written by Phil Marsh