In this paper, an object-oriented approach for Automatic Train Operation (ATO) is discussed in order to compare it to the traditional event-oriented software developed and now used on most of these kinds of systems. In the last decades, the object-oriented approach has been used in a growing number of applications because it supplies flexibility and understanding easiness for the applications. The UML (Unified Modelling Language) supplies many tools for project analysis and documentation. The various UML diagrams allow many points of viewing the project: the static dimension (class diagrams), the dynamic dimension (sequence and state diagrams) and the method dimension (data flow diagrams). The ATO systems, however, had their development aligned to microprocessors development. So, the ATO software has born on assembly form, because ATO systems were concerned with microcontroller applications. With the rise of the C language, many ATO functions were developed in the C language and added to libraries. This was a first step on building pattern routines for ATO functions treatment. The C language allows firmware commands to be handled in a high-level way and this ability led its use for electronics systems controllers. Nowadays, on Sao Paulo's subway system, about 77 trains have ATOs with microprocessors. Among these trains, about 19 trains have ATO software developed in the C language and no train has ATO developed by the object-oriented method. So, this paper analyses the object-oriented approach feasibility for ATO systems. For future applications, we are studying the use of fuzzy logic for train movement control and also studying the development of an ATO fuzzy control software based on the object-oriented approach.
