Search results for " railway"

Numerical study for a new methodology of flaws detection in train axles

2013

Train loads and travel speeds have increased over time, requiring more efficient non-destructive inspection methods. Railway axles are critical elements; despite being designed to last more than 20 years several cases of premature failure have been recorded. Train axles are inspected regularly, but the limits associated to the traditional inspection technologies create a growing interest towards new solutions. Here a novel non-destructive inspection method of in-service axles based on non-contact data collection is presented. The propagation of surface waves, generated by a thermo-elastic laser source, is investigated using a finite element method based on dynamic explicit integration. Coup…

Laser ultrasonics for defect evaluation on coated railway axles

2020

Abstract This scientific paper focuses on the application of an advanced non-destructive technique for an effective inspection of railway axles. The method pertains to ultrasonic techniques, which are widely used in the railway field. The experimental investigation was carried out on simulated defects tooled near the cross section reduction of the axle, in order to simulate fatigue cracks which, due to notch effect, can trigger crack propagation and axle failure. The aim of this research activity is to evaluate how efficiently the proposed technique detects defects and to verify its applicability to axles with a black coating for protection. In view of the experimental setup, comprising a p…

Nuove stazioni, periferie e città

2016

L’infrastruttura contemporanea amplia e fa slittare il proprio campo semantico, trasformandosi definitivamente da artefatto tecnico di carattere titanico ed epico ad elemento riparatore dei tessuti urbani, flessibile, trasformabile. In questo quadro in mutazione, numerose esperienze negli ultimi trent’anni hanno affermato in Europa occidentale il ruolo dei grandi progetti ferroviari come vettori di trasformazione urbana. A quindici anni dall’avvio della prima stagione di concorsi internazionali banditi per le nuove stazioni dell’Alta Velocità in Italia, è possibile un bilancio volto non solo al semplice confronto dei risultati direttamente pertinenti la realizzazione e l’esercizio dell’oper…

Mechanical characterisation and 3D fractional viscoelastic modelling of railway sub-ballast rubberised asphalt

SAFETY PROBLEMS AND GLOBAL COMFORT IN RAILWAYS OPERATIONAL MANAGMENT

2008

In the planning process of a railway intervention and in its operational management, it needs to analyse carefully the relations between the different classes of variables constituting the complex system “vehicle-infrastructure-environment” to find the most suitable actions in optimisation the travelling comfort and safety, with respect for the ecosystem compatibilities. The problem can be tackled, in a systematic way, according to set theory and vector analysis, in a hyperspace Âd of d-dimension up to determining a characteristic global comfort vector that can be combined with each alternatives of intervention in the transport network examined. From this point of view, after the proper ach…

The Rail Quality Index as an Indicator of the “Global Comfort” in Optimizing Safety, Quality and Efficiency in Railway Rails

2012

AbstractThe proposed model uses the stochastic dynamic programming and in particular Markov decision processes applied to the Rail Quality Index (RQI - Italian Indice di Qualità del Binario, IQB).By performing the integrated analysis of the classes of variables which characterize the overall service quality (in terms of comfort and safety), the proposed mathematical approach allows to find the solutions to the decision-making process in function of the probability of deterioration of the state variables of the infrastructure over time and of the flow of available resources.

Criteria for Laboratory Studies on Fine Soils Treated with Lime

2011

When selecting the appropriate materials for constructing road infrastructures, an important way for minimizing both the economical and environmental impact is to make use of lime for treating those natural soils that, involved in the earthwork for opening road fences, are not suitable, as they are in nature, to fulfill the specific requirements for being used as part of road construction, such as road embankments (including the capping layer) or the improved subgrade or, again, the sub-formation. From this point of view, the treatment of fine soils with lime (if needed, with lime and cement) can be considered as one of the main measures for preserving the natural environment since it fulfi…

A markovian model as a tool for optimization of maintenance planning on the railway lines

2008

This paper is designed to develop a procedure which defines a planning criterion for railway superstructure maintenance by means of Markov decision processes. This methodology allows to formulate a specific policy π which carries out the best configuration of budget allocation (min. Ф), and at the same time to guarantee the highest efficiency level in the railway superstructure. Thanks to the dynamic programming technique applied to decision processes, the report has examined the possibility of establishing the best management policy in order to maintain adequate safety levels of implementation and quality speed levels, in the presence of budget constraints, thus optimizing the available re…

The interaction between rail stations and urban area in medium-sized towns. A case study for Trapani.

2012

Dopo l'obsolescenza. Progetti per i viadotti ferroviari dismessi

2013

This article focuses on the increasing number of abandoned railways converted into new parkways, briefly investigating them trough the prism of obsolescence. Over the past forty years, the features matching with the average lifetime of infrastructural buildings have became of growing relevance dealing with contemporary policies in restructuring our territories. In the beginning of 21th century, facing the new challenges of the post-carbon era, cities of developed society are riddled with technical ruins, testaments to their recent productive past. Since the entanglement of transport infrastructure, industry and architecture highly represents important segments of 20th century urban tissues,…