Abstract
Development and maintenance of information systems is one of the most frequent tasks of IT professionals. As such they are key problems of software engineering.
Software engineering concerns mainly on so-called "standard" information systems being typically used in offices or enterprises. Information systems used in trains are in this sense to some extent unusual.
They include critical processes necessary for train control. They also have other specifics like standards and processes or enterprise culture.
We will show that they are the basic reasons for high demandingness of train information systems for development and maintenance in comparison with accordingly large "standard" counterparts. We will propose principles of architecture of the prepared train information system and we will discuss the consequences of the specific requirements and means of their implementation.