Efficient Deployment of Dual Locomotives in Regional Freight Rail Transport

The present article focuses on the efficient deployment of dual locomotives in regional rail freight transport considering the quantification of traction energy and energy savings. In the first part of the article, a categorization of dual locomotives, according to their power output in electric and alternative traction (and ratio of both power outputs) is proposed. The potential of deployment of chosen dual locomotives in Central European conditions (a sub-network of Czech railway network around mainlines electrified with AC) is verified by calculation of traction energy consumption of the model train (with two examples of dual locomotives). In addition to non-stop running through the entire line, traction energy consumption of stop (and following acceleration) in each intermediate station is calculated, for a particular direction. Then, appropriate freight train paths for passing passenger trains and saving of traction energy are proposed. The results are supplemented by sensitivity analysis in the form of calculation of traction energy consumption with variable numbers of loaded wagons, with the help of iPLAN/FBS timetabling software. The limitations are the maximum length or gross mass of the train. Finally, the conclusions obtained from the computational examples are evaluated and recommendations for appropriate deployment of dual locomotives and planning of targeted improvements of infrastructure are formulated.