Extra sections

No, an extra could not have sections. BUT SP (and maybe other roads) had a practice of scheduling second and third class trains at eight hour intervals in ONE direction over some subdivisions. The timetable authority conferred by those schedules would then be used to run what in effect were extra trains, and those often did run in sections. And in some cases "extra" freights would run as following sections of passenger trains. This gets pretty esoteric, and not having been a dispatcher, I'm not particularly qualified to explain it in detail, but "tricks" like that were used to simplify trainorder dispatching in busy territory. Dispatching by trainorder was a fascinating art, and could result in endless debates of the details by aficionados.