select search filters
briefings
roundups & rapid reactions
Fiona fox's blog
The Virgin train travelling through Cumbria slid down a 40ft embankment. One person died and 22 were seriously injured.
Professor Roderick Smith, Royal Academy of Engineering Research Professor, Imperial College London, said:
“Many commentators have commented favourably on how well the carriages withstood this high-speed derailment. Great strides were made in the crashworthy design of trains in the latter years of British Rail. The Research Division based at Derby carried out a huge programme of world-leading research into both structural and internal crashworthiness of trains. The results of this work were incorporated into design standings for the industry and are reflected in all new trains which have been built since. I was privileged to be the Chairman of this activity, and am delighted that the contributions of the engineer working on this programme have proved so successful and have been recognised as such.
“However, it is doubtful that such important and extensive work could be carried out in the privatised railway of today. It is a matter of regret that real railway research has slipped off the radar, although it is acknowledged that some useful development work is still being performed. The railway of the future faces great challenges of safety, reliability, flexibility maintainability and environmental performance. There is an urgent need for a national research contribution.”
Cliff Perry, Vice Chairman of the Railway Division, Institution of Mechanical Engineers , said:
“Inside a British passenger train vehicle is one of the safest places on earth. In terms of a safe railway, we have just passed two complete calendar years together (2005,2006) without a fatal train accident or collision. This has never been achieved before in the history of UK railways. If it had not been for the suicide who parked his car on the railway at Ufton Nervet in 2003, it would have been four years.
“The engineering design and contribution to this is huge. As well as the design, the build standards for trains are closely controlled to ensure compliance with the design strength, and energy absorbing features. This has led to what are seen as project delays, but at times like this the value is proven.
“The aim of train management in a derailment has a number of components.
1. To keep the vehicles upright and in line. This is why the conventional hook arrangements have been completely replaced by significant coupler assemblies. The mode in which the couplers allow the ends of vehicles to come together is important as well.
2. The engineer is helped in this by the fact that under Newton’s laws of motion, a body will continue in a straight line unless a force is applied to divert it. Curves (and any obstructions) on the railway clearly provide such forces.
3. To keep the main body structure intact so that passengers are kept inside.
Laminated glass windows help here, although they are difficult to break and get out of in an emergency evacuation.
4. To reduce the accelerations/decelerations experienced by the passengers.
“In particular the ends of the vehicles are designed with a crumple zone that absorbs energy and reduces the peak forces. High forces represent high decelerations. However, the high levels of energy contained in a fast moving train that weighs hundreds of tonnes means that the longer you can take to slow down, the better it is. The Cumbria train slowed over some half mile according to reports, this helps.
“If it had hit something substantial like a bridge or a train going the opposite way, then the stopping distances are considerably reduced, the energy levels too high to control, and more severe impacts result.
“If done well and successfully, the decelerations felt by the passenger in a train accident are much much lower than those experienced in car accidents, which is one of the factors that make seat belts inappropriate for trains.
5. Items that could be hit by passengers inside the train are then designed to take the loads but cause minimum injury. Tables and seats in particular should absorb impact and collapse gently. They should have rounded absorbent edges.
“It is actually safer to have your back to the direction of travel, but in many railways (e.g. Japan) the passenger preference for facing the direction of travel is so strong that all the seats are turned at the terminus to face the front. It is not a good idea to have heavy luggage on the rack, and modern racks leave smaller spaces. This sometimes annoys the customers with heavy bags, but overall it is safer.”
Professor Colin Porter, Chief Executive of the Institution of Railway Signal Engineers, said:
“If it was a points failure that’s the sort of thing that can easily happen. I wouldn’t expect it to take them too long to find out if it was points. When that has been established you would want them to ask questions like – had the points been checked recently? What condition were they in? etc.
“It’s a miracle that there appear to be so few casulaties and this would seem to be because the carriages largely stayed together and the people were kept cacooned inside. There has been some research done to show that it’s better for people to be kept inside than when windows break and people are ejected through the windows.”
Prof Sir DEN Davies, Fellow of the Royal Academy of Engineering, said:
“What is clear from this accident is how far we have come in making carriages stronger and safer. This is example of a train which has derailed and jacknifed travelling at speeds of around 90 miles/hr with few fatalities. The small number of injuries is in a large part due to the train retaining its structural integrity and not breaking up or bending.”
Prof Roger Kemp, Professor of Engineering, University of Lancaster, said:
“The reports of a train which swayed and bumped suggests a track failure rather than a train failure. A points failure is one of the more likely reasons a derailment like this may occur. If you are driving a car and need to change direction you would use the steering wheel. A train on rails can’t just change direction like a car does; instead trains use a points system to change direction by moving from one track to another. A points failure means that rather than cleanly changing rails the train is left with some wheels bumping along on the sleepers. Because of the difficulty in changing direction on a train, the points are one of the more crucial systems in terms of rail safety. There are thousands and thousands of points on the rails systems in the UK and very few incidents of points failure.
Imagine what the rate of casualties would have been if 180 people had been in buses which rolled off the motorway. This accident actually highlights the engineering advances that have been made over the past few years to maintain the structural integrity of trains and keep passenger safe.”