Software Reports

Preparation of software reports

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.:

  • EN 50657 ‘Railway applications: Rolling stock applications; software on board of rolling stock, excluding railway signalling applications’
  • EN 50128 ‘Railway applications: Telecommunication technology, signalling technology and data processing systems; software for railway control and monitoring systems’
  • EN 61508 ‘Functional safety of electrical/electronic/programmable electronic safety-related systems’


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. 

Procedure for safety classification

For safety classification, we discuss the hazards that are relevant to the product with the manufacturer or operator. This results in an assessment which, for example, follows the risk graph of the SIRF procedure and which is assigned to a specific safety level (SIL). Fault tree analyses are a tried and tested means of clarifying what part of the technical responsibility for the product falls on the software. Here, the allocation of safety responsibility to software, hardware and operational measures becomes transparent. We conduct the inspection in the form of an audit and document the results on site. The outcome is an assessment report.

Procedure for software reports

In order to generate a software report, we review, in discussion with the software manufacturer, whether the standard (e.g. EN 50657) has been fully implemented. Each requirement of the standard is discussed and evaluated section by section with the software developers, testers or quality managers.

We conduct the inspection in the form of an audit and document the results on site. The result is a transparent and reusable report that represents an excellent basis for future changes.