The central aim of this paper is to provide an up-to-date snapshot of hybrid and hydrogen technology-related developments and activities in the North American heavy haul railway setting, placed in the context of the transportation industry more broadly. An overview of relevant alternative propulsion technologies is provided, including a discussion of applicability to the transportation sector in general and heavy haul freight rail specifically. This is followed by a discussion of current developments and research in alternative and blended fuels, discussed again in both general and specific settings. Key factors and technical considerations for heavy haul applications are reviewed, followed by a discussion of non-technical and human factors that motivate a move toward clean energy in North American Heavy Haul systems. Finally, current project activities are described to provide a clear understanding of both the status and trajectory of hybrid and hydrogen technologies in the established context.

The makeup of mixed-manifest freight trains is often determined through rigid operating rules designed based on steady-state in-train forces under nominal vehicle and track conditions. Despite compliance with these rules, excessive forces experienced during exceptional situations still hold significant potential to result in derailments. This paper presents a case study involving a mixed train derailment in a sharp curve following an undesired brake release. The operating conditions and sequence of events are modelled using a novel multiscale simulation approach to combine industry-established longitudinal and multi-body dynamics simulation packages. The root cause of the derailment in this case study is assessed, along with the effectiveness of subsequent rule changes in mitigating the corresponding risk. The case study and results are further discussed in the broader context of a research initiative to utilize near real-time data collection from wayside and vehicle-mounted measurement systems, together with robust multiscale simulation approaches, to improve the area of mixed train marshalling.