The main motivation for building a railway via Beattock was that it could serve both the Scottish centres of commerce: Glasgow and Edinburgh. As far back as 1835, surveys had been completed determining the viability or otherwise of various routes. The Beattock route enabled the line to diverge north at Carstairs, with a Y-junction connecting the Glasgow and Edinburgh branches. The decision to build via Beattock was controversial: could motive power of the day negotiate the steep inclines? Political and financial arguments also ensued – would a single line be more economical than two, and would it serve the commercial interests sufficiently?
The Caledonian Railway built its line from Carlisle to Beattock in 1847, and the line was extended to Glasgow and to Edinburgh in 1848, both routes going via Carstairs. The lines eventually competed with the Waverley route from Carlisle to Edinburgh via Hawick and the Scottish Borders region, and with the North British line from London to Edinburgh via Newcastle. The Glasgow and South West Railway (GSWR) also provided a service from Carlisle to Glasgow via Stranraer. So there were four lines northbound from England to Glasgow and/or Edinburgh.
An independent branch, the Moffat Railway, just over one and a half miles long, ran between Beattock and Moffat. It was opened on 2 April 1883 and was taken over by the Caledonian Railway, by Act of Parliament, in 1889.
The Railway Act 1921 caused the Caledonian to be absorbed into the London, Midland Scottish (LMS) railway, in an exercise known as Grouping. The LMS ran trains direct from London to Glasgow and Edinburgh, as well as throughout other parts of its extensive network. The backbone of the LMS was the West Coast Mainline (WCML) via Beattock.
From its inception, bankers were used to assist most engines and their trains up the gradient.
The gradient from Beattock Station to Beattock Summit, running ten miles, averages between 1 in 69 and 1 in 88. Bankers were initially Caledonian Railways (CR) class 439 0-4-4 engines, then CR Pickersgill class 944 4-6-2 tanks, being replaced over time with LMS 2-6-4 Fairbairn tanks (and ultimately with Class 20 diesels). But engines were often borrowed from other depots, to help out in busy periods or perhaps to rotate engines through onerous banking duties.
The Moffat branch served vistors to the local spa, a popular destination that needed a service of twelve to fifteen small trains per day. These comprised a Drummond 0-4-4T CR class 194 with three carriages. By the 1930s this was replaced by the so-called 'Moffat Bus' or 'Puffer', a steam railcar.
With the demise of steam, banking became less common and was eliminated completely by 1974 with the completion of electrification of the WCML and the introduction of the electric expresses.
Beattock depot closed in 1967 and the station closed in 1972 . At the Summit the sentinel signal box has been demolished and the trackplan simplified. But there are still passing loops and cripple sidings to remind us of the steep gradients and times gone by.