This document corresponds to the subsequent part of ISO 23300-1 "General requirements and test methods for rail welding" and specifies the requirements on rail aluminothermic welding, including the requirements for approval of an aluminothermic welding process, laboratory tests, contractor/welder, as well as the acceptance criteria of aluminothermic welds in track. In this document, 43 kg/m – 75 kg/m new flat bottomed rails of the same profiles and same steel grades are the subject of welding. This document is restricted to butt welding for connecting rail ends. This document does not cover safety regulation of welding operation. Compliance with the requirements of this standard does not of itself ensure the suitability of a welding process for specific conditions of track and traffic. This standard does not cover welds made between different rail sections, differently worn rails and different rail grades.