Indeed - it is also used for single line working on double track in the case of an obstruction, including engineering work, under all forms of block working, be it track circuit block or absolute block.
Essentially, unless all signals admitting trains to a single line section are locked with each other so that nothing can get into the section from either end while another train is in the section, a token or staff has to be carried (or if permitted, the staff can be shown to the driver and a specific ticket for that journey handed to him if another train is following.)
If no token or staff is available, a pilotman has to do the job. He gets authority from the signalman for the train to proceed, gives that authority to the driver, and if the next train through the section is coming from the other end, he travels with the driver as the token/staff.
Some sections are permanently worked by pilotman - Mullingar-Athlone (Formerly ETS Mullingar-Moate and TCB Moate-Athlone, Mullingar has been converted to TCB and Moate is closed) and Lisburn-Antrim (formerly TCB, signals disconnected and loops at Ballinderry and Crumlin clipped (query lifted?) - the panel is still present in Antrim signalcabin, which has been reduced to a gate box, and the panel is unusable anyway)
Another example used to be Antrim-Bleach Green. I think the line was singled in about 1989, and from then on it was worked by Electric Token Block from Antrim to Belfast York Road, and later Belfast Central. Until its closure for refurbishment about ten years later, it was used as a diversion route - I remember in 1995 the Belfast-Lisburn section was closed between Botanic and Adelaide for works related to the new Great Victoria Street station, and trains from Antrim had to run via Bleach Green to reach Belfast, rather than the then main route via Lisburn (as above). To save trains running the whole way to Belfast to exchange tokens, they instituted pilotman working for the weekend so that trains could pass each other on the double track section between Bleach Green and Monkstown.