## 1 Introduction  
The Brazilian railroad transport system has received significant investments in recent years. In order to balance the Brazilian transport matrix, the rail system, which currently corresponds to 15% of the total transportation in the country, is intended to represent 30% of transported loads in the next 10 years. According to the Ministry of Infrastructure, this objective makes it possible to reduce the cost of transport, as well as to improve the logistical efficiency of Brazilian agribusiness [1]. For this expansion to occur, Brazilian railroads are looking to increase the performance of their assets. Wheel/rail interfaces have great potential to improve the competitiveness of the railroad. In addition to reducing maintenance costs, the purpose of this work, the literature shows secondary gains with improvements in wheel/rail contact, such as reduced fuel consumption, reduced derailments, and increased mesh capacity. According to [2], the wheel, as an important part of the freight rail car, directly affects the quality and safety of operations. For rolling stock, wheel consumption generally represents the highest maintenance cost and is among the highest total costs of a railroad. Therefore, the understanding of the variables that influence wear and, consequently, lead to reductions in the useful life of wheels, must be investigated. VLI Logistica, one of the main Brazilian railroads, has developed technical studies for this purpose. The case study applied in this work will focus on the wear of wagon wheels in the Centro Norte corridor, 720 km long, which is characterized by a broad-gauge (1600 mm) railroad that is predominantly used for grain transport using hopper wagons. With such an extensive fleet, it is essential to use equipment along the track, known as waysides, to monitor the vehicle conditions and predictive maintenance [3]. It is known that wheel wear is directly related to the bogie railway suspension. Therefore, correlations obtained through regression between data samples from the wheel monitoring system and the bogie, as well as the use of dynamic simulations, will allow for an analysis of wheel wear. Thus, it is possible to perform statistical modeling to identify the wear function and improve the maintenance strategy of the highest-cost component. In this work, the evaluated parameters were obtained through laser measurement systems known as wheel views, which measure the main wheel parameters. The useful life of a wheel corresponds to the total kilometers traveled until it is scrapped. At present, the average useful life of the wheels in the Centro Norte corridor is 0.8 million km, which is a low value compared to those for other railroad companies, with wheels of 1.7 million km [4]. Therefore, it is necessary to develop strategies to increase wheel life and reduce maintenance costs. The failure mode of VLI wheels is due to flange wear, a condition in which the flange reaches the minimum safety limit of 21 mm. The wheel is then reprofiled on the lathe in a workshop to recompose the flange, leading to a reduction in the thickness of the rim. This cycle continues until the rim thickness is minimal and there is no more material to be removed. Therefore, the wheel life is determined by flange wear in conjunction with reprofiling practices, which implies three useful lives can be obtained. For the AAR-1B Narrow Flange profile used in the VLI, the flange initial thickness was 32 mm. The most common wheel failure mode is flange wear [5], which is a consequence of the friction between the wheel and the rail. To restore this flange, a substantial amount of metal is removed from the wheel rim. The wear can be explained by the wheel and rail contact theory. In the wheel-rail contact patch (Hertz ellipse), two main situations can occur: adhesion and slip [6]. This creepage occurs due to the slipping velocity between the wheel and the rail at the wheel-rail contact patch. This creepage can be divided into three components: longitudinal, lateral, and spin.