PSI - Issue 22

Cristina Reis et al. / Procedia Structural Integrity 22 (2019) 189–193 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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1. Introduction The railway is one of the most important transportation methods worldwide. With land urbanization, the necessity for accessibilities and mobility have emerged. Every day, there are thousands of train travels, transporting people, products, chemicals, fuels, etc. (Oggero, et al., 2006). The European railway network was formed by a different kind of networks, according to the country, each with its own characteristics. When built, central governments aimed at unifying their people and cities, often ignoring the connections out of boundaries. The result, was an incompatible European network, leading several governments to build new tracks or modernize the existing ones (Martí-Henneberg, 2013). In Portugal, the railway implementation follows similar patterns as other European countries. The first Portuguese railway was built in 1856 between Lisboa and Carregado, served by a British second-hand locomotive. The attention was given by the society and the amount of money involved, private entities started investing in building new tracks across the country. Therefore, twenty years later, Portugal ’s main railway was already designed. Although, the construction cost was higher than expected and the traffic estimation was overrated, forcing investors to dismiss their investments. Portuguese central government was enforced to take over the costs from three essential lines: Alentejo, Linhas do Sul e Sueste; Linha do Norte and; Linha do Douro. At the beginning of the twenty century, every Portuguese cities were served by the railway system. The train carriages were built with wood and stops were frequent to refill the locomotive with water (Expresso, 2016). However, since the 1990 decade, the Portuguese government has closed several lines and stations across the country, deactivating over than 1300 km from the existing 3658 km. The Portuguese railway can be summarized in the coastline axis Braga-Lisboa-Faro, with few complementary lines. Nowadays, the Portuguese government has announced and started some modernizations works in specific routes until 2020, but the tracks will not be able to allow high-speed trains, unlike the reaming European countries (Expresso, 2016). Despite the railway is considered one of the safest transportations means, the railway demands constant investment in accident prevention and studies about accidents causes. In 2017, Europe witnessed 1855 railway accidents, some of them with several fatalities. According to the former Railway Transport National Institute (INTF), now included in the Portuguese Transportation and Mobility Institute (IMT), the following concepts are important to understand (INTF, 2006):  “Serious accident” – Any accident involving, at least, a moving rail vehicle that causes deaths or serious injuries at least, one-person, or considerable damage to the material, roads, other installations, or to the environment, or prolonged disruption of circulation. Accidents in workshops and warehouses are excluded;  “Accident” – A sudden, unwanted or involuntary event or chain of events with harmful consequences. Accidents fall into the following categories: collisions, derailments, level crossing accidents, accidents with people caused by moving rolling stock, fires and others;  “Incident” – Any occurrence, other than accident or serious accident, associated with the operation of the railway and affecting the operation safety. All events (broken rails, tourniquets, signaling failures, overshooting of the most restrictive aspect (SPAD), broken wheels and axle breakdowns) must be reported. If one of these events leads to an accident, it must also be reported. In the railway systems, there are 7 types of accidents that can happen (INTF, 2006):  Derailment – When the train goes off the track. Getting off a track into another which isn’ t desired, may also be a derailment. It means any situation in which, at least, one wheel of a train leaps from the rail;  Collision – Train collision, including collisions with obstacles in the jig, means a collision which may be frontal between trains, between the front and the tail of two trains, between a train and any part of another train, or the collision of a train with maneuvering movements, fixed objects (such as line ends), objects temporarily present on or near the track (such as rocks, landslides, trees, rail vehicles lost parts or road vehicles) and railway maintenance machinery or equipment;  Fire – rolling stock fires concerns to fires and/or explosions that happen on railway vehicles during their travel or operations;  Structural collapse – Not directly related to railway accidents are the ones resulting from structural collapses, like bridges, tunnels or the permanent way. These collapses are mainly due to structural failures in engineering works, landslides, soil erosion, among others;