The Garnkirk and Glasgow Railway was an early railway built primarily to carry coal to Glasgow and other markets from the Monkland coalfields, shortening the journey and bypassing the monopolistic charges of the Monkland Canal; passenger traffic also developed early in the line's existence.

It opened officially on 27 September 1831 using horse traction, and had the track gauge of 4 ft 6 in (1,372 mm) that had been adopted by the Monkland and Kirkintilloch Railway, with which it was to connect.

In the eighteenth century, the city of Glasgow experienced increasing demand for coal, both for domestic and industrial purposes; the most convenient source was the Monkland coalfield, south of Airdrie, but the distance of over ten miles incurred considerable expense in the absence of an efficient means of transport.

The chief sponsors included Charles Tennant & Co, who had their St Rollox Chemical Works at Townhead, Glasgow, adjacent to the Monkland Canal.

However the promoters decided it would be advantageous to shorten the extent of usage of the rival M&KR line, and to make the gradients more favourable to loaded traffic.

Accordingly, the route was from the junction with the M&KR at Gartsherrie, near the Gargill Colliery, running via Gartcloss, Gartcosh, Garnkirk, Robroyston, Milton, Broomfield, Germiston, Rosebank and Pinkston to terminate at the Glasgow depot at Townhead.

The M8 motorway and Springburn Road junction system has obliterated the site, but it was approximately at the present-day western end of Charles Street.

It was designed to be a locomotive line from the outset—a far-sighted decision, although it incurred considerable extra expense in heavier track construction.

Elsewhere on the line fish bellied rails to Birkinshaw's patent—another far-sighted decision—at 28 pounds per yard (14 kg/m) in 15-foot (4.6 m) lengths were laid on stone blocks each weighing 3 long hundredweight (340 lb; 150 kg).

[2] Now following swiftly on from the opening, a passenger service was started on 1 June 1831, running from the G&GR Townhead terminus and Leaend, on the margin of Airdrie, on the Ballochney Railway, the trains operating intermediately over the M&KR.

On 30 July 1840 the service started, involving a passage on the canal from Port Hopetoun in Edinburgh; traversing the Slamannan company's line, which included a rope-worked incline at Causewayend; the Ballochney Railway, including the double rope-worked inclined place at Commonhead; the Monkland & Kirkintilloch Railway between Kipps at Gartsherrie; and the G&GR itself.

It lasted until February 1842 when the Edinburgh and Glasgow Railway opened, putting paid to any through traffic over the Slamannan route.

[14] In this period, attention was being drawn to the high cost of operation of the line; in 1839 - 1843 gross revenue was £15,337 and working expenditure was 51.3% of that sum.

A more fundamental issue was the intensive traffic over the M&KR section, crossing a junction of main roads at Coatbridge.

Moreover, the Wishaw and Coltness Railway (W&CR) relied on the M&KR section to convey coal from its line to the G&GR.

When it sought parliamentary authority it changed its name to the more appropriate Glasgow, Garnkirk and Coatbridge Railway (GG&CR).

The Caledonian Railway offered considerable extra traffic, by connecting to the Wishaw and Coltness line at Garriongill, and continuing to Glasgow over it and the GG&CR.