>
> Does anyone know what methods are used for single lines outside the English
> speaking world?
I presume you mean other than schemes using track circuits or axle
counters etc.
Much of Europe has various forms of automatic single-line working, even
including contacts in overhead wiring on lines where only electric
vehicles run.
So far as non-automatic systems are concerned, there is a
very wide spectrum ranging from train orders through various token
systems,
to schemes with block instruments, to timetable or virtually nothing at
all.
Eddie Oliver