[rexpress]

SelTrac has been around since the mid 80s, and was originally a German developed product (Standard Elektrik Lorenz) based on LZB technology.

My understanding of LZB is limited, but it appears to be a fixed block system with wayside detection of trains, albeit with shorter blocks than lineside signals would usually have. This is different to SelTrac which is moving block.

[mschuster91]

Yeah, LZB internally is based on fixed blocks - but on a system with block lengths down to 50 meters (as in the Stammstrecke München [1]), the difference is negligible.

Crazy to see that SelTrac was actually developed in Berlin, failed there, but is still in widespread use across the world.

[1] https://de.wikipedia.org/wiki/Stammstrecke_(S-Bahn_M%C3%BCnc...