Yes, I use this service occasionally, boarding the train in Vielleville. This is a "ligne secondaire", so the service is neither frequent or fast, but it's a pleasant enough alternative to driving.
Trains from Gueret leave at: 06.22, 07.38, 09.10 & 12.51. Return times are: 15.53, 17.27, 18.40 & 19.03. The journey takes just over an hour, depending on how many stops it makes, not all trains stop at all the stations and this is a weekday timetable, there is only a limited service on Saturdays, and none on Sundays, except via La Souterraine, by bus!
Hope this helps,
Kind Regards, Mike