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The Haytor Granite Tramway was a tramway built to convey granite from Haytor Down, Dartmoor, Devon to the Stover Canal. It was very unusual in that the track was formed of granite sections, shaped to guide the wheels of horse-drawn wagons. It was built in 1820; the granite was in demand in the developing cities of England as masonry to construct public buildings and bridges. In 1850 the quarries employed about 100 men but by 1858 they had closed due to the availability of cheaper Cornish granite. The Haytor rocks and quarries are protected from development and disturbance as a Site of Special Scientific Interest. ==Operation and purpose== The granite from the quarries near Haytor Rock was much in demand for construction work in the cities of England, but in an era when railways and reliable roads had not yet been developed, the transport of this heavy and bulky commodity was a significant problem. Coastal shipping was a practicable transport medium, and the Stover Canal was available from Ventiford to the Teign Navigation. The Haytor Tramway was constructed to carry the granite the to the canal, which involved a falling vertical interval of to the basin of the Stover Canal. Its form was a close relative of a plateway, where longitudinal L-shaped metal plates were used to support and guide the wheels of wagons. In the Haytor case, the "plates" were cut from granite blocks; the upstand guided the wheels of the wagons. As the wagons had plain wheels without flanges, they could be manouevred at the terminals without the need for sidings and points. The gauge of the track was , and at junctions the wheels were guided by 'point tongues', pivoted on the granite-block rails. Authorities differ on whether the point tongues were oak or iron. In the upward direction, the empty tram wagons were pulled to the quarries by teams of horses; the loaded trams were run downhill by gravity to the Stover Canal basin at Ventiford, Teigngrace. The route was carefully engineered to follow a consistent downward gradient to the canal basin, following the contours of the land (although one of the upper branches had a contrary gradient, requiring horse draught in the loaded direction). A siding at Manaton Road may have been used to allow trains to pass when meeting in opposing directions. The Stover Canal had been built between 1790 and 1792 by James II Templer (1748–1813) of Stover House, Teigngrace, for the clay traffic, and was extended to Teigngrace in 1820. From here the granite was carried by canal boat to the New Quay at Teignmouth for export by ship, the quay having been built in 1827 for the purpose, making midstream transshipment no longer necessary.〔 In 1829, due to financial difficulties, James Templer's son George Templer (1781–1843) sold Stover House, the Stover Canal and the Haytor Granite Tramway to Edward St Maur, 11th Duke of Somerset (1775-1855), whose family had long owned the nearby large Berry Pomeroy Castle Estate. George Templer left Devon, only to return a few years later and build a new mansion at Sandford Orleigh on the outskirts of Newton Abbot. He became the granite company's chief Devonshire agent. The wooden flat-topped waggons had iron flangeless wheels and ran in trains of usually twelve waggons drawn by around 18 horses in single file, in front for the upward journey and at the rear for the downward.〔 An old sailor called Thomas Taverner wrote a poem which gives us this information: The vehicles used were probably adapted road waggons and were about long, with a wheelbase of . The wheels were in diameter with a tread, and were loose on the axles. The twelve-wheeled reference in the poem above means 'twelve waggons with wheels'.〔 Stover House itself, then the home of the Templer family, had been constructed of Haytor granite in 1781. Granite's popularity as a building material was increasing and the reason for the quarry and tramway's creation was most likely a contract for George Templer to use the stone for London Bridge. Part of the British Museum, the old General Post Office in London and the Waltham Monument in Ludgate Circus were built of Haytor granite in the 19th century. The last use of Haytor quarried granite was the building of the Exeter War Memorial. The splitting of the granite was done by a method known as feather and tare, which had replaced the former 'wedge and groove' method around 1800; this more reliable method being another reason why the use of granite had become practicable. The new method worked by means of a series of holes was made along a potential line of fracture using a tool called a 'jumper'. ''Feathers'' were metal prongs with a curved upper end. Two of these were inserted into the holes, the curves in opposite directions at 90 degrees to the line of potential fracture. A wedge-shaped metal ''tare'' was hammered between the two until the granite fractured. The granite trade was always somewhat sporadic with fluctuating production and indeed no granite was produced or transported between 1841 and 1851 and the quarries and tramway had closed by 1858. Several thousands of tons of granite had been quarried some years, but competition from Cornish granite quarries with cheaper transport put paid to the business and the tramway fell into neglect, however its robust construction and low recyclable value meant that it was never lifted and much has survived the passage of time. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Haytor Granite Tramway」の詳細全文を読む スポンサード リンク
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