Slightly OT but I remember Neussargues from my first non-UK train travel in the summer of 1983. We got a local DMU from Aurillac (which stopped at loads of tiny village stations sadly now closed - France appears to have had its Beeching perhaps 20 or 30 years after ours) to there.
Many would say that France's "Beeching" equivalent actually took place a generation
before ours: in 1938, when nationalisaton (merging of the several big quasi-private companies, as the SNCF) was accompanied by what was called transport "co-ordination"; whose chief component was closure to passengers of a huge number, country-wide, of branch and secondary / tertiary main lines, of the new SNCF (in the majority of cases, these lines were retained for freight), in favour of bus services. Rail closures (lines, or minor stations) since then, went on "few and slowly" for some decades after; then at a greater pace in the late 20th / early 21st century -- but generally reckoned "piecemeal", rather than as one holocaustic plan.
I remember seeing the electrified line coming up from the south and thinking it was a major trunk inter-city route (maybe Montpellier-Clermont-Ferrand-Paris?) but then being surprised that just about nothing was using it and wondering what the point of the electrification was!
This seemingly "isolated-ish" electrification, has a historical basis. The Neussargues -- Beziers line started life as part of the route between Paris and the Mediterranean, of the partnership between the Paris -- Orleans, and Midi, Railways: rivals for "capital-to-Med." traffic, with the Paris -- Lyons -- Mediterranee Railway's routes further to the east. North and east / west of Neussargues was PO trackage; south thereof to Beziers, was Midi. The Midi railway was from early-ish in the 20th century, an enthusiastic pioneer in electrifying many of its lines -- with its running through much mountainous country, ideal for hydro-electric schemes. The PO, further north, was less interested in electrification. Thus the Midi electrified up to Beziers, I think circa 1930: the part of the north -- south main line, north of Neussargues, remained steam through the 1934 merger betwen PO and Midi; and nationalisation in 1938.
The line through Bort-les-Orgues, as mentioned below: its decline can be reckoned to have begun in the early 1950s. Till then, it was part of the above-described PO / Midi north -- south route; which southward from Montlucon (that town still having a passenger service from the north AFAIK) ran to the junction of Eygurande-Merlines, thence through Bort-les-Orgues south-east to Neussargues. In the early '50s, a massive hydro-electric project involved the flooding of a long stretch of the section between Eygurande-Merlines and Bort-les-Orgues. This caused abandonment of the whole Eygurande-Merlines -- Bort section, and the end of any main-line role via Bort: from then till late-20th-century closures, it was a matter just of two branch lines, Bort -- Neussargues, and Bort -- Miecaze junction -- [Aurillac].
Ironically, after closure of Eygurande-Merlines -- Bort: north-south long-distance passenger hereabouts was transferred to the erstwhile rival PLM route, as far as Arvant south of Clermont-Ferrand, where the ex-PO east-west line diverges westward, first significant point reached being Neussargues.
So Aurillac-Bort les Orgues was open in 1983 by the looks of things.. interesting!
I'm sure I only recall Aurillac having three lines at this time: to Clermont-Ferrand, to Toulouse and to Brive. How frequent was the Aurillac-Bort-les-Orgues service?
Actual point of divergence of the line traversed by Aurillac -- Bort workings, was Miecaze (mentioned by me above -- also mentioned by
peteb), a good many kilometres out westwards along the line to Brive. Maybe this fact tended to make the existence of the Aurillac -- Bort service, less than obvious?
Also Bort-les-Orgues to Neussargues? Did the Aurillac -- Bort extend to Paris? (e.g. as a once-a-day trip) or was it a local DMU? From Wikipedia, it looks like this line used to be a through line towards Paris at one time.
(My bolding above) -- see my text "above-again", re happenings around Bort-les-Orgues.
Looking at the map it really does look like a delightfully rural and isolated circuit, going through very sparsely populated countryside and some big loops on the Bort-Neussargues section, presumably to get round hills. Bort-les-Orgues looks like an interesting natural break if doing the circuit in a day: a rural town with an impressive rock outcrop (the Orgues or organ-pipes of the place-name). These lines look like the sort of route that in the UK would be gone by 1963, never mind 1983 - but sadly now gone by the looks of things.