At the beginning of the twenty-first century, one of the major challenges of humanity was to reduce the negative effects of civilization development. Besides the engines used in road vehicles there is a large group of engines for non-road applications. This group includes motor propelled vehicles not used on the road NRMM (Non-Road Mobile Machinery). Engines of these vehicles, among all of the non-road applications, are characterized by very specific working conditions that do not allow for them to be qualified for propulsion engines. The main problem with these vehicles is the particulate matter and nitrogen oxides emission. Rail vehicles operating conditions these requirements take by the similar way, as having a wide range of rolling stock markedly alters the environmental impact of these vehicles. Thus it becomes necessary to consider the issue of the method of evaluation of engine emissions in rail vehicles in terms of their actual operating conditions. Thus, efforts to assess the actual level of emissivity for rail vehicles and attempts to improve it are necessary and justified.