The paper summarizes the issue of calculation of CO₂, PM and NOx emissions within the framework of updating the methodology of regional distribution of traction diesel consumption in railway transport according to locomotive performance in individual regions of the Czech Republic. Within the project, activity data for categories of traction vehicles according to Tier 2 in the framework of the Emission Inventory Guidebook 2023 methodology were calculated and traction diesel consumption for line-haul locomotives in passenger and freight transport and for diesel railcars was calculated. Based on these values, it was possible to accurately calculate the emissions from traction diesel consumption in rail transport within individual regions of the Czech Republic, in accordance with the IPCC Guidelines 2006 and EIG 2023 methodologies. The update of the methodology for calculating traction diesel consumption and emissions of pollutants has thus generated data that are also well suited for regionally focused tasks in modelling the environmental impacts of transport.