Kontron has realized a CompactPCI based train control system for the French railways. There are approximately 200 control units and 2000 field units on the track connected by Ethernet. Such mission critical systems require 100 percent reliability. Therefore the fail-over control units are designed with two different hardware and software technologies for redundancy: An x86 based part with the a 3U Intel® Pentium M CPCI board, the CP306, running under Linux RT-OS and a PowerPC 8540 based part with LynxOS. If any failure occurs in one system, regardless if software or hardware, the redundant system takes over. The outdoor units placed on the rails are equipped with the E²Brain Computer-on-Module, due to features like extended temperature range, resistant to harsh environment conditions, and high reliability.