The route connected at either end with established railways - the Maybole and Girvan Railway at one end and the Portpatrick and Wigtownshire Joint Railway at Challoch Junction at the other, using running powers over the latter to gain access to Stranraer. The G&PJ diverged from the 1860 line from Maybole a short distance north of the latter's terminus in Girvan and built its own through station (Girvan New) at the foot of the steep bank that took the line onwards to its summit at Pinmore.
The line remains open throughout, as part of the Glasgow South Western Line between Glasgow and Stranraer, although all the intermediate stations apart from Barrhill were closed in 1965. Regular freight services to and from the depot at Stranraer Town operated over the line until the early 1990s, but these ceased following the withdrawal of the Railfreight Distribution wagon load service by BR in 1991. The passenger service is irregular (with large gaps between trains) as it operates mainly in conjunction with the Belfast ferry sailings and is constrained to some degree by the single track nature of the line (there are only three passing loops on the line south of Girvan, at Barrhill, Glenwhilly and Dunragit).
The line is currently a key part of the Carrick & Wigtownshire Community Rail Partnership SAYLSA which comprises local Community Councils, representation from South Ayrshire Council, First ScotRail as well as private individuals.
A recently completed rail study  commissioned by the SPT, Passenger Focus and SWESTRANS has recommended that the timetable be recast where possible to encourage new passenger business (mainly by providing a more evenly spaced service) and also to seek to develop new freight flows such as timber from Barrhill, grain from Girvan and intermodal traffic between Northern Ireland and Scotland (and beyond).
Butt, R. V. J. (1995). The Directory of Railway Stations: details every public and private passenger station, halt, platform and stopping place, past and present (1st ed.). Sparkford: Patrick Stephens Ltd. ISBN1-8526-0508-1. OCLC60251199.