The South Wales coalfield extends to the sea at Swansea, and therefore was immediately accessible to shipping at a time, before the nineteenth century, when land transport was limited to what pack animals could carry on their backs.

[1] Anthracite coal of high quality was available around Llansamlet, and an early wooden wagonway was built from there to a wharf on the River Tawe by George Kirkhouse; it was operational sometime after 1750.

John Scott acquired control of mines on the Gwernllwynchwth Estate and after 1812 built a tram road from there to Foxhole, on the Tawe near its mouth.

Public notice was given in 1840 of the intention to build this railway, but in fact it lapsed, probably due to opposition from the Duke of Beaufort.

Nevertheless, Benson and his partners repaired and modernised the 1812 tramroad and made some extension to it over land in their possession, thus not needing Parliamentary authorisation.

The SVR hoped to sell its line to the South Wales Railway, and the SWR was amenable, but did not have the Parliamentary powers to make the purchase.

[3] In March 1850 the construction of the South Wales Railway reached Llansamlet, and a flat crossing was made by the SWR of the SVR line.

To neutralise objections in Parliament from the South Wales Railway, it undertook that a third rail (to make mixed gauge track) would be laid southward from the intersection with the South Wales Railway, allowing broad gauge traffic access down to Swansea.

[2][4] In 1855 the SVR railway was said to be open for a distance of 6+1⁄2 miles and only carrying mineral traffic; this amounted to 1,000 tons per day[5] with an annual income exceeding £5,000.

Captain Ross of the Board of Trade visited the line but he found deficiencies and declined to permit passenger running.

[2][3] The northward extension had been authorised, but actual construction was slow, largely due to the poor level of subscription for shares.

Even without Midland Railway involvement, this had been desirable for the N&BR company, giving better access to Swansea than running via Neath.

[2][3] The SVR&B&NJR ran into serious financial difficulty; it was unable to secure the subscriptions for shares that it needed to start construction.

It entered into a complex arrangement with a contractor, John Dickson, but he fell into bankruptcy at a time when he himself was heavily indebted to the company.

As a moribund company whose only asset was the power to build a line, it was absorbed by the Neath and Brecon Railway in July 1869, and construction was completed, and it was opened to traffic on 19 November 1873.

[2] The SV&N&BJR was to be leased by the N&BR on completion, but when it was clear that no progress toward that goal was being made, it was amalgamated with the Neath and Brecon Railway on 26 July 1869.

It was submitted for inspection to the Board of Trade for passenger operation, and Colonel Hutchinson visited for the purpose; everything was satisfactory and the first part of the line between Morriston and Upper Bank was opened for goods traffic on 6 October 1871.

[2] For some time, the directors of the SVR had believed that sale to a larger company was the solution to their long-standing financial difficulties.

[14] From this time the Swansea Vale Railway Company was only a financial entity, receiving the lease charge.

Nevertheless, considerable capital expenditure was now being undertaken by the Midland Railway on bringing the SVR track and structures up to date, and this complicated the financial relationship.

The high dividends paid in the final years of the SVR's independent existence had been achieved by not doing enough maintenance of the line or locomotives.

There were a number of track-related derailments in the early period of Midland ownership, and Miles et al attribute them to lack of maintenance.

The Midland was no doubt aware of the poor state of the infrastructure of the network it had acquired, and it quickly set about modernising it; track replacement was an early priority, followed by the renewal of some bridges.

The Midland Railway offered to operate all the N&BR domestic trains north of Colbren Junction for one third of receipts, about £4,000 annually.

Actual construction was delayed by GWR and then by World War I, but a part of it opened in 1922 from Felin Fran to Clydach and in 1923 to Trebanos just south of Potardawe.

[2][3] The SVR network continued to prosper, mainly because of the high-quality anthracite mined within its area; this was considered a premium product, and much was exported to Canada and to France.

[2] After closure, a heritage group named the Swansea Vale Railway Society, leased a section of track between Upper Bank and Six Pit; in 2007 the lease expired, and the group merged with the Gwili Railway in Carmarthen, and moved most of their rolling stock there.