It seems that the Melbourne Train Control System is still running on a hardware "emulated" #PDP11 :) "In this particular train control application it has enabled the life extension of mature train control software, originally designed to run on a now life expired DEC PDP-11 platform to be migrated to a PC based platform. [...] Consequently, the major part of the project was the ‘hardware adaptation’ that was required to integrate the new system into the existing fabric." https://webinfo.uk/webdocssl/irse-kbase/ref-viewer.aspx?refno=1559669757&document=2.10%20strangaric%20-%20legacy%20train%20control%20system%20stabilisation.pdf