From its fi rst day the railways, along with a huge positive impact on the economic development of the regions where they have been built, were cau sing irreparable damage to the ecology of these regions. They were destroying the natural landscape, resulted to the death or to the fragmentation of population of wild animals, polluted the air and created unbearable noise, according to the ideas of those days. Now, when the railways are an integral part of human civilization, it is interesting to evaluate their current impact on the environment, is it as large as sometimes it is presented. The paper provides the assessment of the three main components of this impact: ingredient pollutants, electromagnetic fields and noise of rolling stock. It shows that air pollution by harmful emissions do not exceed one of the other modes of transport, and often is much lower. Electromagnetic fields, generated by the contact network and overhead lines of automatic block signal system, are well below health and safety regulations. The noise of rolling stock, although it gives rise to public complaints where the railways come close to residential areas, can be signifi cantly reduced by using simple technical solutions.