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There is limited information on locomotive design developments that suit Australian needs in terms of practical applications for achieving net-zero-emission goals in rail motive power solutions. The usage of modelling and simulation approaches as part of digital twin technologies for hybrid and hydrogenpowered rail vehicles can be a useful tool to make an evaluation of possible practical design variants of battery storage or hydrogen and hybrid combinations. Recent digital twin research studies in this area, performed at the Centre for Railway Engineering located at CQUniversity, show that the implementation of 6 axle locomotives for these purposes can be problematic due to the existing limitations for sizing and optimising zero carbon energy storage options and train operational scenarios. It is possible to resolve these sizing and optimising tasks with the implementation of 8 axle locomotives. To investigate the feasibility of this option, the digital twin pathway to net-zero carbon dioxide emissions was chosen, an 8-axle freight locomotive digital twin was developed, and the deliverables are presented. [ABSTRACT FROM AUTHOR]

Train driving strategies are dictated by the need for meeting timetabling and energy-efficient control. The magnitude and duration of traction and braking efforts can vary significantly and is strongly dependent on heavy haul train operating parameters. There is a lack of tools to estimate rail wear for a complete network, and considering full train operation, including the contribution of different types of rollingstock. Rail wear simulation studies require high-fidelity multibody models which make the simulation work computationally expensive, and the obtained results often just describe a particular individual vehicletrack interaction case. With the advent of high-performance computing facilities, a full train co-simulation that consists of multiple rail vehicle physics-based (multibody) models can now be performed using parallel simulations in a single run. In this paper, a digital twin method has been proposed to investigate the impact of train driving strategies on rail wear. The method has been demonstrated with a case study. The limitations of the proposed method have been discussed. [ABSTRACT FROM AUTHOR]

Wheel diameter differences (WDD) on railway vehicles impact the dynamic behaviour, traction system performance and result in rail damage. It is well known that the various types of algorithms that govern locomotive adhesion control systems may compensate for the presence of WDD. However, detailed studies on the influence of adhesion control algorithms on rail wear and rolling contact fatigue (RCF), under the presence of WDD have not been published. Furthermore, several standards establish WDD limits for wheelsets, bogies and vehicles which, in turn, determine the planning of wheelset maintenance activities. There is no information in the public domain on how such limits were set and their impact on the dynamic processes at the wheel-rail interface. Thus, a numerical program comprising several multibody dynamics simulations was conducted to study the influence of WDD on vehicle performance, considering several combinations of operational parameters, in-train forces and the responses of a locomotive traction mechatronics system. The digital twin methodology, including the example of results from the numerical program and the analysis of the impact of WDD on rail damage and vehicle performance, are presented. The pathway for the development of digital twins for such tasks is also presented and discussed. [ABSTRACT FROM AUTHOR]

Considering recent rapid developments in the use of rail digital twins, it is necessary to clearly understand the basis for such developments. Digital twins are commonly built in a complex modelling environment and their modelling concepts are based on physical-based models. This process requires great precision with the introduction of non-linear modelling components that have many uncertainties that cannot be described by purely physical models. One such component in the modelling involves the wheel-rail contact couplings that require the introduction of friction characteristics to calculate creep contact forces at the wheel-rail interfaces. The modelling concept assumes that a rail digital twin for a heavy haul line should be supplied with a friction map that would allow modification of the friction characteristics at the wheel-rail couplings based on the variations of wheel-rail contact point locations along the track, which must take into account the real train operational scenarios and tribological aspects observed in the field. In this paper, the methodology for the development of such a friction map and principles for its implementation are proposed and the existing limitations are discussed in detail. [ABSTRACT FROM AUTHOR]