The article presents the basic information about the current situation related to the basic elements of non-electrified railway transport, which are railway lines and traction vehicles. Data concerning the situation in a highly industrialized country like the USA and in Poland are given. The further part presents the numerical data, location concentration and a map of arrangement of non-electrified lines, as well as general information about diesel vehicles. The next part of the article discusses the ongoing and planned purchases and modernizations of railway diesel vehicles. An important part of the article are data about development plans of the non-electrified railway network in Poland. The last part of the article describes the selected information about costs related to activities for non-electrified railway transport, such as purchases and modernization of rolling stock and networks.The second part of the article will be published in the next issue of quarterly Rail Vehicles.