Software reports are prepared to demonstrate the safety of software for components, rolling stock, signalling systems, control centres or other technical systems. The safety classification of the software into Safety Integrity Levels (SIL) can be found at the beginning of each assessment report.
Various sets of rules can be used in the process, e.g.:
In the area of European TSI approvals, the manufacturer is free to choose the preferred way to demonstrate software safety. EN 50657 is often regarded as the industry standard in this regard but can be too rigid for some applications.