Nowadays, the railways in the Russian Federation are moving to the path of seamless construction. The development of technologies to ensure the possibility of continuous welded rail track with the desired quality characteristics is the actual direction now. One of the key technologies for the construction, repair and maintenance of a seamless path is welding of rails, for which various methods have been developed and are used, such as: electric-contact, gas-press, induction, laser welding, friction welding, aluminothermic, electric arc electrodes, in the environment of protective gases, electroslag, powder wires, etc. The article describes the advantages and disadvantages of the main types of welding rails that are most widespread today: resistance flash welding and aluminothermic welding. It is shown that as the primary method of rails welding in Russia, electric-contact welding is used. However, in connection with the inability to weld rails in the zones of turnouts by contact machines, the use of aluminothermic welding of rails started on the railways of Russia. It has been shown that the most important factors that determine the quality and reliability of welded rails are metallurgical and welding technologies, as well as subsequent processing methods that reduce the impact of high temperature effects. The technological features of these methods, advantages and disadvantages of modern methods of solving problems in welding, as well as economic costs were considered taking into account operational properties of joints. Experience has shown that during the exploitation of welded joints made by aluminothermic method on the railway and at testing on the experimental ring of JSC All-Russian Scientific Research Institute of Railway Transport, their quality is slightly inferior of electric-contact welding. Special attention is paid to the peculiarities of welding technology for differentially thermally strengthened rails. The analysis of existing methods of rails welding allows working out the main directions of research to solve this problem.