The Coatbridge Branch of the North British Railway was a railway built to connect the important coal and iron industrial districts of Coatbridge and Airdrie directly to Glasgow for the North British Railway.

It opened in 1871 connecting an existing network in the Monklands to a College station (later High Street) in Glasgow. This enabled mineral traffic to reach quays on the River Clyde, and passenger traffic was given a considerable boost when the Glasgow City and District Railway opened in 1886, connecting the Coatbridge line with the North Clyde network west of Glasgow.

The line is open today, handling a considerable suburban passenger traffic and through trains to Edinburgh on the Bathgate route.

In the first decades of the nineteenth century there was increased demand for coal in Glasgow, for domestic and industrial purposes. There were limited local supplies, and the Monkland Canal had been bringing coal in from the Monklands pits. In 1826 the Monkland and Kirkintilloch Railway was opened to modernise the transport of the mineral, bringing it to the Forth and Clyde Canal. The line was horse-operated with primitive permanent way, but it was successful in its objectives. Other so-called coal railways followed in the district: the Garnkirk and Glasgow Railway being the first line to reach Glasgow from the Monklands, opening in 1831. It was followed by the Wishaw and Coltness Railway, opening from 1833.

The discovery of substantial reserves of blackband iron ore and the development of the hot blast method of iron smelting revolutionised the iron industry and its centre was in Coatbridge, vastly enhancing the fortunes of the local railways.

The Edinburgh and Glasgow Railway (E&GR) opened its main line in 1842, intersecting the Monkland and Kirkintilloch Railway. In 1845 there was a frenzy of railway promotion in Scotland, and the Caledonian Railway was authorised, to build a line between Edinburgh, Glasgow and Carlisle. To save the cost of building a new route into Glasgow, the Caledonian arranged to take over the Garnkirk and Glasgow Railway and the Wishaw and Coltness Railway, running its main line over them. This gave the Caledonian Railway a roundabout route from Coatbridge to Glasgow, opened in 1848. The Monkland and Kirkintilloch Railway did not join the Caledonian Railway group, and instead aligned with other coal railways (the Ballochney Railway and the Slamannan Railway) to form the Monkland Railways in 1848. For the time being the Monkland Railways had no direct connection to Glasgow, although there was a connection with the E&GR at Kirkintilloch Junction (later Lenzie). Although it developed numerous branches and new lines, these mostly had an eastwards emphasis. The Monkland Railways were absorbed by the Edinburgh and Glasgow Railway on 31 July 1865.

In 1846 the North British Railway (NBR) opened its first line, between Edinburgh and Berwick-upon-Tweed. It saw itself as a trunk line, joining with English railways to form a through route to London. Subsequent acquisitions and openings emphasised the easterly orientation, until on 1 August 1865 the NBR amalgamated with the Edinburgh and Glasgow Railway, so that it now had a Glasgow terminal, at Queen Street. The Monkland Railways had been absorbed by the E&GR the previous day, so now the NBR had a presence at Coatbridge as well. The amalgamations gave the NBR excellent connectivity eastwards from Coatbridge, but the awkward route towards Glasgow remained; this was important because much iron ore and finished iron was exported from quays in Glasgow, and from Ayrshire ports.^{[page needed]} Moreover, the best of the Monklands coal and iron deposits had been worked out; the emphasis on the mineral extraction was shifting to south Lanarkshire, in Caledonian Railway territory.^{[page needed]}

The NBR set about closing the gap by building a line running directly west from Sunnyside Junction, Coatbridge to Glasgow. The route became practicable because of the promotion of the City of Glasgow Union Railway (CoGUR). This was being done by the NBR jointly with the Glasgow and South Western Railway (G&SWR), and the CoGUR was constructing a line crossing the River Clyde in Glasgow. In the early days there were ideas of through express passenger services between the North British Railway (former E&GR line) and the G&SWR routes, although this concept was not much developed, and the majority of the CoGUR was absorbed by the G&SWR. However, there was to be a large modern goods depot at College (later High Street). Hitherto the NBR had been much criticised for its poor goods facilities in the city; and through mineral train workings to the General Terminus and Glasgow Harbour Railway and the Ayrshire ports were to be enabled. The CoGUR line opened in 1871 as far as Bellgrove; the onward section to Sighthill took several more years.