This diploma thesis "Principles of Equalizing the Tractions-engines Power Output of Foreign Provider of Railway Services" aims to delineate how inequalities in power output emerge and how they are later equalized by provider of railway services. This is one of the crucial topics for operating and putting together international trains. The theoretical basis is then used in the applied part of this thesis to describe and evaluate tractions-engines power output of selected foreign provider of railway services on Czech railway network. For better description there is also a balance of tractions-engines of power output enclose at the end of this thesis to illustrate the position of Czech Railways abroad. The analysis made in the applied part put stress on differentiating the long distance transport from cross-border international transport of passengers. Furthermore, this thesis deals with the implementation of the European Rail Traffic Management System (ERTMS) in the connection with compatibility of the Czech railway network to neighbouring rail networks with emphasis on train safety appliances and the project European Train Control System (ETCS).