[2] The circular route back to Central station via Shawlands and Maxwell Park was completed on 2 April 1894.

The Newton and Neilston branches were built to provide a through route from the Lanarkshire coalfields to ports such as Ardrossan on the Ayrshire coast.

The lines originally carried significant amounts of freight, but commuter trains are the only regular users now.

The existence of a commuter railway was a major factor in the development of Glasgow's southern suburbs, although until electrification in 1962 there was virtually no passenger service beyond Kirkhill[3] by this route.

There was a trial run on the previous day,[4] with over 5,500 passengers reported as using the new trains in their first morning rush hour.

Round the west side of the Circle onto the L&AR lines eastbound, terminating at Kirkhill.

East side services ran to Newton, with many extended to Motherwell via the Clydesdale Junction Railway.

From May 1984, both the Newton and Neilston services remained 2 per hour, none turned back at Kirkhill and only one ran the full circle each way.

At peak times the above services combine to have trains running approximately every 5–10 minutes between Glasgow Central and Cathcart, where line capacity permits.

The line now features a number of different services, however these are considerably reduced from levels prior to the COVID-19 pandemic.

This was due to a number of Class 380s being reserved for driver training on the newly electrified Glasgow to Edinburgh via Falkirk High route.

Most recently, in December 2008 Transport Scotland's Strategic Transport Projects Review suggested an upgrade of the Circle to light rail as part of a wider light rail network for Glasgow, incorporating both new lines and re-purposed older alignments.

[6] If taken forward, this proposal was supposed to have been implemented during the period 2012 - 2022, in line with the scope of the strategic review.