Introduction
Complying with the Decision no 1692/96 of the European Parliament and of the Council of 23.07.1996 to upgrade the trans-European conventional rail network to be equipped for speeds of the order of 200 km/h with axle load not less than 230 kN, most of Rail Tracks Boards use high-manganese cast steel for scissors crossovers (ca. 13% of Mn). The problem occurring during usage of this cast steel is welding of a rail track having a pearlite structure with high-manganese scissors crossovers of austenitic structure. It requires to use special separator from austenitic steel (Cr-Ni) with a cross section of a rail track making possible to join a rail track and the scissors crossovers together. Moreover, it is very hard to weld the steels with highly different microstructure and the chemical composition [1]. More and more common usage of steels with bainitic structure [2÷4] to produce the heavy-duty rail tracks encourages to investigate the possibility to use similar materials for scissors crossovers in a form of monolithic cast blocks as well. Apart from all built-up issues concerning proper casting of monoblock from bainitic cast steel, the paper focuses on correct design of chemical composition of such material. The best verification of project study are CCT diagrams made for test casts [5÷7].