Underground railway systems are an intrinsic part of modern city living, enabling a wide variety of human activities, from work to leisure. Unfortunately, metro and commuter trains remain vulnerable to attack, as highlighted by the 2004 Madrid bombings and the 2005 attack in London. The improvement of the safety of metro systems with regard to terrorist attacks has been addressed by many researchers in order to implement a line of defence to isolate these causes and consequences, in order to prevent the attack from occurring and, should it happen, to mitigate its consequences as much as possible. In the framework of the European FP7 SecureMetro project, researchers from different fields are studying various improvements to metro vehicles in order to improve the resilience and survivability of the vehicle, its passengers and the transport system as a whole, in order to minimize the material and human damage caused by a bomb or a fire, improve the capacity to resume normal operation, and thus make public transport systems a less attractive target for terrorist attacks.