What is "seltrac"

SELTrac is a digital signalling technology used to control the movements of rail vehicles originally developed by Standard Elektrik Lorenz (the "SEL" in the name). It was originally developed for the Krauss-Maffei Transurban automated guideway transit system developed in the 1970s, and moved to the ICTS vehicle when the Transurban efforts were taken over by an Ontario consortium. First used on the Scarborough RT in Toronto, SelTrac was the first fully automatic moving-block control system to be used in production.

SelTrac was primarily sold and developed by Alcatel, through a Toronto subsidiary. SelTrac is now sold by Thales, after it purchased many of Alcatel's non-telephony assets. New versions were made for different markets, and today SelTrac is used for rolling stock control around the world.