Abstract - This paper gives a proposal of an advanced interlocking software for a Computer Interlocking System (CIS). Hence the system can become a standard system, independent of track layout and the country of application. The main contribution is conversion of the operational, functional and safety requirements of an interlocking system into the general interlocking software. There is also a new way of presenting a control table which can be entered as a simple data file and control table conversion to the interlocking functions suitable for computer application. An advanced method of screen design showing the layout of a railway station is proposed as well. 

Keywords - Computer system, real-time control, fault-tolerance, railway signalling, interlocking system, safety critical software, safety analysis, control table.