The Wemyss Private Railway was a network of lines, sometimes known as the Wemyss Estate Railway. The lines were a group of mineral and other railways in Fife, Scotland, mainly on the land of the Wemyss family. They were built to connect coal pits to harbours and the railway network, for the use of tenants of the Estate. The Wemyss and Buckhaven Railway was built at the expense of the Wemyss Estate and carried passengers; it was later sold to the North British Railway.
When numerous collieries needed a railway connection the Wemyss Estate built a connecting line to Methil Harbour and improved the harbour itself. The local network became known as The Wemyss Private Railway and the Estate's interest was transferred to the Wemyss Coal Company. These terms have been used interchangeably by authors.
The collieries were nationalised in 1947 and the sidings connections at the pits followed; the main line railways of Great Britain were nationalised in 1948, but the central section, now known as the Wemyss Private Railway remained in private hands. However the mineral activity in East Fife declined and in 1970 the Wemyss Private Railway closed down.
The family of Wemyss was "unquestionably the oldest on the County", tracing its line back to Michael Wemyss, who died in 1165. In 1633 the title of Earl of Wemyss was bestowed, but the heir to the title, David Lord Elcho engaged in the Rebellion of 1745, and was later attainted, and was unable to succeed to the title. A junior branch of the family succeeded, and in 1820 James Erskine Wemyss became the head of the family. He died in 1854, and was succeeded by James Hay Erskine Wemyss. On his death in 1864 his eldest son Randolph Gordon Erskine Wemyss (1858 - 1908) was heir to the lairdship at the age of six. It was in trust until his majority; the Trustees managed the affairs of the Estate, led by his Mother.
The Estate comprised very extensive lands in the County of Fife, and coal was mined on estate lands from at the latest the eighteenth century. Randolph Wemyss was possessed of an exceptionally dynamic business mind and developed the mineral extraction; as he did so it emerged that huge quantities of winnable coal lay under the lands of the estate.
Coal had been worked in Fife for many centuries, probably since the thirteenth century. As well as its household use it was extensively used for salt panning; sea water was evaporated by heating to produce salt, an essential commodity, and in the sixteenth century the area around Methil and Wemyss had the most extensive group of salt pans in Fife, all belonging to the Wemyss Estate.