The train disaster in Viareggio-Italy: root causes of failure by outcome results from criminal case preliminary investigations

The authors presented on the ICEFA IV in Cambridge (UK) the first part of this work concerning the biggest train disaster occurred in Italy on the 29th of June 2009, a 14-car freight train carrying liquefied petroleum gas (LPG) derailed in the Viareggio station. Derailment was provoked by one axle broken due to a fatigue crack propagation. Head 4-wagons derailed and capsized, while the first tank wagon encountered at final stroke one object that penetrate the tank shell causing vast LPG leakage. Two minutes after, outlet LPG from first tank spread in civil building close to railway station causing 32 dead victims. The authors - appointed as forensic technicians of several injured parties - were involved in 2011 in preliminary investigations, namely the examinations in the Italian Criminal Procedure follows up by technical experts appointed by judge and those one appointed by parties. Technical investigations aimed to clarify root causes for axle failure and the tank wagon breaking, namely the two major contributing causal events for the top-event “fire explosion”. A deep failure analysis was conducted on fractured components: fractographic, microfractographic and metallurgical analyses in general were performed on broken relevant parts. Fatigue crack propagated for long time and started from corrosion pits. By an engineering point of view, this forensic analysis pointed out evidences that authors consider relevant for drawing recommendations to be submitted to Public Authorities. Dramatic impacts that hazardous freight transport can have on civil safety in case of fails in maintenance procedures, in monitoring and supervising safety systems, in inadequate risk assessing have been highlighted. Main fails were all in contrast with the railway safety directive 2004/49/EC that force Member States to give priority to the prevention of serious accidents ensuring railway safety to be continuously improved in a reasonably practicable way, taking into account technical and scientific progress.