In general, the railways have kept their systems highly safe and reliable through the ongoing efforts over a period of many years. This has been achieved primarily by continuous improvements, which mean that there is a dearth of experience in the introduction of innovative new systems.
Therefore it is said that comparing a new system that features a completely new architecture with a conventional one may be difficult. With this in mind, we developed a method of evaluating the effect of a new system architecture and took a radio-based train control system as an example. Then we described the result of a case study that evaluated the realtime, safety and reliability properties of the new train control system.