Towards A Bomb-Proof Underground?

The Madrid bombings of 2004 and the 7/7 London Underground attacks of 2005 killed 191 and 52 civilians respectively. The horrific scenes of carnage and destruction vividly demonstrated the devastating reality of explosives detonating inside confined rail carriages. The NewRail programme based at Newcastle University’s School of Mechanical and Systems Engineering, and funded by the EU’s SecureMetro project, is tasked with reducing this potential. In the future this is likely to spawn a whole new generation of ‘bomb-proof’ tubes, but has already had notable successes developing carriages which are far more resilient to explosives detonating inside them.

The project’s sphere of activity concentrates around two primary aims; containing the impact of the blast, and reducing the amount of resultant debris – which is often the foremost reason for fatalities, not necessarily the explosion itself. These engineers have also explored ways to revise the dividing structures, both between and within carriages, by introducing energy-absorbent materials to reduce blast velocity.

Analysing train wreckage from 7/7 alongside controlled, yet full-scale, explosions of a variety of Over and Underground carriages, the team were able to better understand the nature of explosions within rail vehicles. Particularly the way in which the wave travels along the length of the carriage. A better appreciation of such blast mechanics is also key to understanding how the interior furnishings react to the force. Addressing such vulnerabilities, proposals for the re-designed and target hardening of current trains has resulted in a prototype (which itself has undergone full-scale testing) specifically with blast resilience in mind. Securing ceiling panels and seating with retention wire, applying plastic layer coating to windows, replacing heavier equipment with light-weight alternatives, and introducing energy-absorbing materials, were just some of the key alterations made.

“Preventing flying objects is the key. Tethering ceiling panels reduced the risk of fatalities and injury from flying shrapnel and also meant the gangways were kept relatively clear of debris, allowing emergency staff quick access to the injured… The windows are blown outwards – putting anyone outside, such as those standing on a platform, at risk from flying glass.  With the plastic coating applied you see a clear rippling effect as the blast moves through the train but every window remains intact, apart from the safety windows which are designed to be easily knocked out.”

Conor O’Neill, Newcastle University’s NewRail research centre

Replacing the entire Underground network with new ‘bomb-proof’ carriages is clearly both impractical and economically infeasible in the immediate future. Nonetheless, incorporating new blast-resilient technologies and materials into existing units, to create trains which are better able to withstand terrorist attacks is an intelligent move in the short-term. How the PR and information campaign that surrounds these upgrades is handled will also be key; increasing public awareness will both improve the commuters feeling of security and reduce the appeal of the Underground as a potential terrorist target.


Photo credit: dChris

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