This document specifies requirements concerning the approval and/or homologation of welding processes, contractors, welders, inspectors and acceptance of welded joints in the factory and/or track.

This document is applicable to the following rail welding processes:

1. flash butt welding (FBW);
2. gas pressure welding (GPW);
3. aluminothermic welding (ATW);
4. enclosed arc welding (EAW).

In this document, 43 kg/m to 75 kg/m new flat-bottomed rails of the same profiles and same steel grades are used as the subject of welding.

This document does not specify requirements or test methods specific to each welding process. These are to be prescribed in the subsequent parts of the ISO 23300 series.

Concerning butt welding, this document is restricted to connecting rail ends.

This document does not cover the welding for construction of crossings, railway switches, signal bond installation or restoration of rails.

This document does not cover any safety regulations for welding operations.

In this document, the qualifications of individuals and organizations that are approved by the railway authority for rail welding are not specified.