[2][page needed] The line was single track throughout, serving a region of very low population density, but it achieved significance by carrying heavy traffic, both passenger and goods, to and from northern Irish destinations through Portpatrick and Stranraer.

[3][page needed] As early as 1620 Portpatrick had been established as the port for the short sea route between south-west Scotland and the north of Ireland, at Donaghadee in County Down.

Irish cattle and horses were a dominant traffic early on, and Post Office mails developed later: by 1838 8,000 to 10,000 letters passed through the port daily, brought by road coach from Dumfries, and from Glasgow.

When local interests promoted a railway branching from it at Dumfries and running to Castle Douglas, the G&SWR actively supported it, in fact subscribing £60,000 towards the little company's capital.

The government indicated tentative support for such a sea connection, and for improving the harbour at Portpatrick, so the committee proceeded; on 19 September 1856 plans for the route of the British and Irish Grand Junction Railway were tabled.

The route east of Newton Stewart took a markedly northerly course through bleak terrain, and this may have been to avoid competing with coastal steamers on a more southerly alignment.

On 28 March 1860, they decided that "the board should retain the working of the line under their own management" Evidently this had been foreseen, and provisional arrangements for the supply of locomotives had already been made, and this was quickly followed by contracts for rolling stock and for signalling equipment.

It had subscribed £60,000 to the PPR on the assumption that the little company would effectively belong to it, and had promised a further £40,000: it now made that sum conditional on an impossible contribution by the Belfast and County Down Railway.

[8] Dalrymple, as chairman, told his shareholders that the loss of the £40,000, though "attended with great inconvenience" need not "make any material, or at least, permanent, financial embarrassment".

[note 4] The line was single throughout, worked by telegraph order; crossing stations were at Castle Douglas, New Galloway, Creetown, Newton Stewart, Glenluce and Stranraer.

This was in advance of the Board of Trade inspection by Captain Tyler, on 2 December 1862, when he reported "that the opening of this branch would be attended with danger to the public using it by reason of the incompleteness of the works".

[11][page needed] Smith describes an incident illustrating the primitive state of Portpatrick Railway resources: Portpatrick was a brute of a place to get out of—a great grinding curve, and an up-grade of 1 in 57, the whole in full track of the westerly gales, even in the rock cutting where the blow hole up at the Tailor's Peak let the salt spray in to coat the rails.

[4][page needed] Convinced that Irish traffic would be profitable, the CR acquired two small paddle steamers and operated a service between Stranraer and Belfast from 4 December 1865.

As they had accepted the commercial risk of revenue income which was now lacking, this might seem reasonable; but the PPR successfully argued that this was not provided for in the Working Agreement, and they refused to share the money.

On 29 August the vessel, named Aber, was rammed in thick fog by an Atlantic steamer and sank in five minutes; the new service had lasted 12 days.

[7][page needed] If the Post Office was unwilling to support Portpatrick, they were not opposed to taking advantage of a route that did not need massive capital expenditure, and from March 1871 they agreed to pay £1,500 annually for the carriage of mail over the PPR, on the basis of trains running in direct connection with night mail trains on the main line.

This encouraged the PPR to support a Larne and Stranraer Steamboat Company in running a daily return crossing on that route, from 1 July 1872; the vessel was the Princess Louise.

The council was unwilling to execute the work, costed at £6,000, and after considerable wrangling, the PPR obtained authorisation to take over the pier, by the Portpatrick Railway Act 1877 (40 & 41 Vict.

The WR decided to work the line itself, and were pleasantly surprised to receive a letter dated 7 January 1875 from Thomas Wheatley, who had (it transpired) recently resigned under a cloud from the North British Railway, where he had been locomotive superintendent.

Goods traffic started on 3 March 1875 and a passenger service to Wigtown was begun on 7 April 1875 with some four-wheel coaches, thought to be second-hand from the LNWR.

It opened on 3 April 1876, and four trains daily ran from Newton Stewart to the new Garliestown station; the earlier one was renamed Millisle and downgraded to goods service only.

Fresh parliamentary authority was obtained in the Wigtownshire Railway Act 1877 (40 & 41 Vict.. c. li) to extend the share capital and to legalise the Garliestown branch.

The CR and its English partner, the London and North Western Railway (LNWR) naturally wished to retain control, and the power struggle reached a stalemate.

[4][page needed] Domestic operation did not change much at first; but the London trains ran from Dumfries to Carlisle via Annan rather than via Lockerbie, with a significant time saving.

[4][page needed] The G&SWR now got a share of the working; their train crews had no familiarity with the route at first, and the Caledonian Railway refused to provide conductors.

When the state of the permanent way was assessed, "the Ministry of Transport was a bit shocked ... so the entire PP&W main line was put under a 45 mph restriction till it could be reballasted and relaid.

By the end of the year, Large numbers of troops were now stationed in Northern Ireland, and the ordinary passenger [train] service proved quite inadequate for men going on leave to England and Wales.

[21]Later in the war it was decided that an emergency west coast port should be established, to continue transatlantic trade in the event that Glasgow or Liverpool docks were disabled by enemy action.

Smith speculates that if the port had been needed at full capacity, the limited rail access over difficult single lines (from Dumfries and from Ayr) would have been challenging.

[7][page needed] The gradients on the Portpatrick Railway main line were severe: gently undulating from Castle Douglas to New Galloway, they then formed a stiff climb at 1 in 80 to Loch Skerrow, the alternately falling and rising at 1 in 76 to the summit at Gatehouse of Fleet.