On March 11, 2004, 10 explosions ripped through four commuter trains in Madrid, killing 191 people and injuring 1,800. A little more than a year later, on July 7, 2005, three bombs exploded on the London metro, killing 56 people and injuring 700.
Engineers in Europe are now investigating methods to reduce casualties in the event of future terrorist attacks. The project, called SecureMetro, is run by Conor O’Neil, senior research associate at the NewRail research center at Newcastle University and includes a team of European engineers who are looking for ways to retrofit existing train and subway car designs to make them more resistant to bomb attacks.
“We were looking for things you can do after the design stage,” O’Neil said.
The researchers refitted one decommissioned subway car with existing equipment and then compared how that car fared in a bomb explosion to another exploded subway car that wasn’t modified at all.
They found that it wasn’t necessary to use exotic new technologies. For example, putting a sheet of plastic on window glass prevented the shards from scattering during a blast. It’s similar to the technique used on car windshields to keep glass from flying during collisions. Tying down the ceiling panels also made a difference. “These kinds of panels are designed to be removable,” O’Neil said. “Putting a loose metal wire that runs from the panel to the substructure keeps them in place. It also works for speakers – if they become detached they don’t become projectiles.” Cutting down the amount of flying debris also makes it easier for emergency services to get into a car if a blast does occur, since there isn’t a lot of stuff blocking the aisles.
Another idea that came out of the analysis, though not tested directly, was redesigning the joints between the metal bars that passenger hang on to. Ordinarily they are bolted together, but expansion joints could make them more flexible, so they absorb some of the energy of the blast.
The research team looked at terrorist attacks stretching back 60 years. One thing they noticed was a change in tactics. O’Neil noted that in the 1970s, the Irish Republican Army might call authorities ahead of time with a code word, offering the chance to evacuate. Terrorist groups — at least in Europe — were interested in property damage rather than deaths. More recent attacks have been designed to maximize casualties.
O’Neil said he hopes to share information with transit agencies including those in the United States. “We’re also looking to speed recovery,” he said. “To get things working as soon as possible and limit the impact of the attack.”
There’s no way to make a subway car blast-proof like a tank, said O’Neil, because unlike a bomb attack against a tank or military truck, a bomb blast on a train is probably going to come from inside rather than outside. But with some simple modifications, it is possible to reduce the number of deaths and injuries.