Coal and other minerals were extracted in the west of Scotland from medieval times; getting the heavy product to market was always a challenge, and this encouraged the development of tracked systems; the earliest plateways[note 1] in the vicinity of Ayr date from—at the latest—1775.

[2][3] In 1831 the Ardrossan Railway opened; it too was a horse-operated line using stone block sleepers, but passenger operation was a major part of its objective.

However, the promoters were unable to raise sufficient money to build the whole of their line; moreover recent improvements to the navigability of the River Clyde enabled sea-going ships to reach the city.

Nonetheless, it was a considerable commercial success, carrying passengers and in enabling coal, particularly from the pits belonging to the Earl of Eglinton to be exported at Ardrossan, and it further emphasised the viability of railways.

The cost was to be £550,000 and a 10% return could be expected; notwithstanding the south-westerly course of the line, it was foreseen as a first step towards linking with railways in England.

[4] After a directors' special run between Ayr (north of the river, at Newton-on-Ayr) and Irvine on 19 July 1839, the line opened to the public between those points on 5 August 1839.

On 13 July 1840 the joint line between Paisley and a temporary terminus in Glasgow at Bridge Street was ready for a demonstration run, opening fully to the public the following day.

[4][8][12][13] The opening of the line and the conversion of the Ardrossan railway to run in connection, enabled a fast service—26½ hours—between Glasgow and London to be instituted.

The fast steamer Fire King plied on alternate days between Ardrossan and Liverpool; from May 1841 the English terminal was transferred to Fleetwood following the opening of the Preston & Wyre Railway and Dock Company.

The locomotives available at the time were not thought to be capable of climbing the steep inclines, and rope haulage was put forward by some as the solution.

By contrast, a route from Kilmarnock through Cumnock and Dumfries—the Nithsdale line—would have much easier gradients and pass through considerable population centres, bringing in additional traffic.

The government intervened and in 1839 appointed two royal commissioners to determine the way forward; at this time there was a presumption that one railway route from Scotland to England would suffice; but which?

An independent Glasgow, Dumfries and Carlisle Railway was proposed, to build from Carlisle to meet the GPK&AR, and the GPK&AR itself proposed several branches, mostly for tactical reasons, to weaken or exclude the Caledonian Railway (CR), as the dominant supporter of the Annandale route.

[10] The CR case was strengthened by its intended branch to Edinburgh;[note 3] moreover locomotive designs were being improved, and the capacity to haul trains over the steep gradients of the Annandale route was diminishing in importance.

The shareholders approved the lease of the Kilmarnock and Troon Railway (K&TR); as a horse-operated plateway this would need to be converted and upgraded at a cost of £40,000, but the process would give much improved access to the harbour for collieries in the area.

[15] The 1846 session of Parliament experienced a snowstorm of bills for new railways; many of these threatened to encroach on the GPK&AR area of influence and abstract business; several schemes were promoted by the Caledonian Railway or its allies; in self-defence the GPK&AR itself promoted numerous schemes—in fact 25 branches as well as a bill nominally by the K&TR to authorise the modernisation works—to head off some of the encroachment.

The act of Parliament stipulated that on actual completion of the construction, the GD&CR should merge with the GPK&AR to form a new company, the Glasgow and South Western Railway.

Over-optimism led to stark inability to pay up when the calls (for cash on subscribed shares) came in, and suddenly money was impossible to come by.

[18][19] The purchase had earlier been agreed by the proposed Paisley, Barrhead and Hurlet Railway, supported by the GPK&AR, for £34,000.

The GPK&AR had subscribed to £150,000 in face value of the shares of this proposed line, with the sole intention of excluding the Caledonian Railway from the area.

The GPK&AR now petitioned against the bill, but this was unsuccessful, and the Paisley, Barrhead and Hurlet Railway Act 1848 (11 & 12 Vict.

Having a majority shareholding, the GPK&AR was able to stall any plans to proceed with construction of the Hurlet line, but on 9 October a special GPK&AR shareholders' meeting reviewed the financial commitments made by their board in the frenzied days of 1845 and 1846, when support to numerous new lines had been committed; the meeting left the directors in no doubt as to their disapproval.

[4][10] This included the Ballochmyle Viaduct, located near Catrine; it was built with a central span of 181 and 175 feet (55 and 53 m) high above the River Ayr.

It was the largest masonry arch span in the world at the time of its completion, and is the highest railway bridge in Britain.

At Gretna passengers could change to Caledonian Railway trains; the Dumfries station was a temporary structure south of Annan Road.

The GD&CR was insolvent, owing £230,000 and needing £602,000 to complete the line; these facts emerged after another bruising session at which shareholders criticised the liabilities and futile Parliamentary expenses incurred by the directors of both companies.

By March 1849 these negative feelings led to the GPK&AR chairman, James McCall being removed along with several directors; Andrew Orr took over as chairman, but for a period the remaining directors from the earlier years formed an obstructive group; their motivation seemed to be the personal liabilities they had taken on on behalf of the company, and their wish to be indemnified against personal loss.

All the remaining GD&CR construction contracts had been let and were proceeding, and the two companies would operate as a single unit using GPK&AR rolling stock.

[4] The GPK&AR and the GD&CR had already been authorised by the Glasgow, Dumfries, and Carlisle Railway Act 1846 (9 & 10 Vict.

[27] In 1840-1841 twelve 2-2-2 locomotives (designed by company engineer J. Miller)[27] were built and given names such as Bruce, Eglinton, Phoenix, Prince Albert and Loudoun.