The Cathcart District Railway was proposed to serve the arising demand for suburban residential travel on the south side of Glasgow, Scotland. It was planned as a loop running to and from Glasgow Central station, but at first only the eastern arm, to Cathcart via Queens Park, was built, opening in 1886. The western arm was opened in 1894 and trains operated round the loop. A frequent passenger train service was operated, and there was also a limited goods and mineral operation.

The passenger trains were popular but the company was never very profitable, and tramcar competition hit it hard. A decline set in through the twentieth century until electrification in 1962, which revived the line, which served onward routes to Newton and Neilston as well.

The line continues in use today.

The trunk railways of central Scotland developed from 1850 onwards; the Caledonian Railway and the Glasgow and South Western Railway (G&SWR) were trunk railways formed with the intention of linking to the English railway network. Other railways south of the River Clyde led to specific locations outside Glasgow. As the city grew, the notion of daily residential passenger travel arose, at first by the middle classes but increasingly by all levels of the community. Suburban railway facilities were limited, and they were inhibited by the inconvenient location of the Glasgow passenger terminals. Bridge Street station was on the south side of the river close to Glasgow Bridge. It served the Paisley lines. South Side station was located further from the city, south of Cumberland Street; it served the Barrhead, Hamilton and Motherwell lines. Buchanan Street station, located on the north-east side of the city at Cowcaddens Street led by a circuitous railway route to the Motherwell and Carlisle line, as well as the Stirling direction.

This unsatisfactory situation was resolved by the construction of two central passenger terminal stations: St Enoch station, opened by the G&SWR in 1876, connecting to the G&SWR line to Ayr via the Paisley joint line, and to Kilmarnock over the Glasgow, Barrhead and Kilmarnock Joint Railway, opened in 1873. This "magnificent terminal" was centrally situated in the city, and it gave access to all the G&SWR south side lines. In 1879 the Caledonian opened its Glasgow Central station, also well situated, and accessible for all the Caledonian's south side routes.

So from 1 August 1879 both large railway companies had commodious new stations serving their south side network. On 15 November 1879 three suburban railways to the Cathcart area were announced in the press; they were all independent, and all assumed a connection to the new terminal stations; they sought running powers for the purpose. They all planned to leave the Barrhead line at Strathbungo, turning south-east. Two proposed a loop, returning to near the starting point; the third was a simple branch line.

In fact the G&SWR rebuffed the approach of one of the contenders, and this was made known to the others, who reconsidered the St Enoch part of their schemes. The most ambitious proposal was the Cathcart District Railway (CDR) and this was favoured by the Caledonian, which offered (in March 1880) to work the line at cost if it were connected only to their lines. As the Glasgow Barrhead and Kilmarnock Joint Railway, managed independently, was objecting to the running powers application over their line. Accordingly, the CDR withdrew the proposal for those running powers, and their parliamentary bill was unopposed as a result. On 7 September 1880, the Cathcart District Railway Act 1880 (43 & 44 Vict. c. ccix) was passed. The share capital was to be £175,000. The route was substantially the present-day Cathcart Circle, leaving the connecting line between Central station and the GB&KJR line at a proposed Cathcart Junction, near Albert Road (later Albert Drive), running in a loop via Cathcart and returning to a junction near Strathbungo station.

Prior to this the Caledonian Railway had intended to apply for powers to subscribe for shares in the CDR and to work it, but a difference of opinion about the connection to the G&SWR lines resulted in the Caledonian withdrawing for the time being. In the 1881 session, however the Caledonian relented and the Caledonian Railway (Additional Powers) Act 1881 (44 & 45 Vict. c. cxix) empowered it to subscribe 50% of the share issue, and to manage and work the line. Only now, on 7 December 1881, did the company issue a prospectus inviting public subscription. The Caledonian would work and maintain the line for 45% of gross receipts.