Maintainable Software Structure for Train Traffic Control Systems: Sprint

Abstract

More than ten train traffic computer control systems have been operated in Japan. We have participated in the development of almost all of these systems. The quality of the systems was determined by software bugs. System-downs caused by software errors occurred at least as often as those caused by hardware faults. Software errors were often caused by insufficient, incorrect or misunderstood requirement specifications. Software maintenance and enhancement were very difficult because of imperfect requirement specificationsThe above situation has motivated us to develop the software production system for train traffic control systems called SPRINT (Software Production System for Integrated Train Traffic Control). SPRINT provides standard sentences to describe the requirements of train traffic control systems. These sentences are expressed in railway terms so that anyone can understand them easily and correctly. In the early stage of the software production process, SPRINT tests the validity of system requirements described by the sentences. SPRINT also provides the software structure of application programs which realize train route control functions. When system designers modify any part of the application programs, SPRINT transforms the modified programs into requirements and evaluates the influence of the modification