Railway signalling systems have the characteristic of handling data describing the topology of the line they manage. These topological data are said to be invariant, as they only change after work has been carried out on the line. Topological data includes signal lights, points, track circuits, platforms, line descriptions, etc. Topological data is not the only invariant data that can be used by a railway system. There is also data relating to train characteristics: mass, length, maximum speed, maximum acceleration, braking characteristics, door characteristics, bell time on boarding, etc.
Signalling, but also many other railway systems, can therefore be built on the basis of a generic application (applicable to different sites and different users) and a parameterization process to obtain a specific application (dedicated to a site, a use, or a user).
The CENELEC 50128:2011 standard covers both aspects: the development of a generic software application, through section 7, and the development of a process for parameterizing a generic application, through section 8. The aim of this article is to present the problem, the associated notions and the expectations of data preparation, through an analysis of the CENELEC 50128:2011 standard.
A glossary is provided at the end of the article.