Pareto-Based Maintenance Decisions for Regional Railways With Uncertain Weld Conditions Using the Hilbert Spectrum of Axle Box Acceleration

Abstract

Abstract1 -This paper presents a Pareto-based maintenance decision system for rail welds in a regional railway network. Weld health condition data are collected using a train in operation. A Hilbert spectrum-based approach is used for data processing to detect and assess the weld quality based on multiple registered dynamic responses in the axle box acceleration measurements. The assessment of the welds is stochastic in nature and variant over time, so a set of robust and predictive key performance indicators is defined to capture the weld degradation dynamics during a given maintenance period. Using a scenario-based approach, two objective functions are defined, performance and the number of weld replacements. Evolutionary multi-objective optimization is employed to optimize the objective functions so that the trade-offs between performance and cost support decision-making for railway network maintenance. The results of the proposed methodology show that the infrastructure manager can localize field inspections and maintenance efforts on the area with the most critical welds. To showcase the capability of the proposed methodology, measurements from a regional railway network in Transylvania, Romania are employed.

Defining and quantifying railway service to plan infrastructure interventions

“…On the other hand, several studies provide an analysis of the railway service focusing on impacts related to specific stakeholders, mostly for the passengers. Most of them use questionnaires to evaluate the importance of different factorsfor example, delays, safety, comfort, services and information providedfrom the passenger's perspective (Aydin, 2017;Cavana et al, 2007;Chou et al, 2011;de Oña et al, 2015;Eboli and Mazzulla, 2012;Nathanail, 2008;Thomas et al, 2006). Small groups have also investigated the impact of these various factors on other stakeholders.…”

“…Multi-objective functions are capable of quantifying all impacts on service related to different stakeholders due to changes in the state of the infrastructure and, therefore, are often used for this purpose (Ebrahimnejad et al, 2012;Núñez et al, 2019;Su et al, 2017). According to this approach, weights are assigned to multiple technical aspects and parameters based on their impact on service.…”

“…Although this report is a useful source of monetised cost categories, it is not complete, as several cost categories are not considered. For example, vibrations, which can cause discomfort for passengers, as explained in the papers by Nathanail (2008), Eboli and Mazzulla (2012), Chou et al (2011Chou et al ( , 2014 and Aydin (2017), or mobility, which is essential for society, as explained in the paper by Cascetta et al (2011), are not quantified in these studies.…”

“…Depending on the organisational and operational scheme of the railway network, it can be particularly challenging to link directly the impacts experienced by passengers to the infrastructure system. Some examples of such challenging impacts are the unhappiness of passengers due to the infrequency or regularity of train runs, the way that service interruptions are resolved and the quality and quantity of information provided to them before and during the trip (Nathanail, 2008). For these cases, it is helpful to estimate the average cost related to the inadequate state of the infrastructure over the total cost of the impact for a specific time period.…”

Multi-Objective Path Planning for Autonomous Robots Using Reconfigurable Analog VLSI

“…Multi-Objective (MO) decision problems are ubiquitous and encountered in diverse fields such as economics [1], health [2], medicine [3], education [4], transportation infrastructure maintenance [5], energy systems [6], and the topic of this paper, path planning for autonomous mobile robots [7]- [9].…”