Siemens' LZB, an old bomb-proof signalling system
The LZB (Linienzugbeeinflussung, in its German version), the signalling system that manages train traffic on the corridor between Madrid and Seville, is a highly tested technology that works with a proven 99.9% effectiveness since its commissioning in 1992, a contract that at the time was awarded to the German giant Siemens.
We haven't written up this one. Expansion ES has the full story — the link below goes straight to it.