Ecological solutions for freight trains

Abstract

The article presents the potential of freight railway transport in terms of saving of emissions and maximizing the efficiency of operation. Attention is paid to the transport of freight trains on electrified lines with higher gradients (up to 25‰), alternatively with the possibility of a trip to non-electrified lines and sidings, which generate significant extra costs in the operation of trains and are often a reason for the carrier to deploy a locomotive of independent traction (diesel-electric) even in electrified line sections, even at the cost of increased operating costs and increased emissions. There are many such lines and possibilities of use within the Central European region and the Czech Republic.
In the first part of the article, the basic categorisation of dual-mode freight locomotives and their suitability for individual operating programmes is presented. This part also describes current situation on the rolling stock market in general and directions of development taken by various locomotive manufacturers.
Case studies of deployment of real freight locomotives on chosen Czech railway lines are used in the next part to present the possibilities for energy and cost savings when replacing a vehicle with independent traction by an electric or dual-mode locomotive, at least in sections equipped with overhead catenary. The pros and cons of using several possible solutions are described in detail. Further considerable savings can be achieved by, among other things, using regenerative braking and returning the generated electricity back to the catenary system when driving downhill. In this respect, however, it is also necessary to cooperate with the infrastructure manager, who must also adapt the railway lines to the operation of these vehicles.
Finally, general rules for operational deployments on which the replacement of a conventional vehicle by a dual or pure electric vehicle can be considered are formulated.