Background
James Henry Greathead was born on August 6, 1844 in Grahamstown, Cape Colony, South Africa.
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James Henry Greathead was born on August 6, 1844 in Grahamstown, Cape Colony, South Africa.
He migrated to England in 1859, and in 1864 was a pupil of P. W. Barlow, from whom he became acquainted with the shield system of tunnelling with which his name is especially associated.
Working with P. W. Barlow, Greathead modified a smaller shield, circular in cross section designed by Barlow, to complete the Tower Subway (1869) under the River Thames near the Tower of London. He began to practise on his own account, and mainly divided his time between railway construction and taking out patents for improvements in his shield, and for other inventions such as the "Ejector" fire-hydrant. As the shield was pushed forward by screw jacks, the tunnel behind it was lined with cast-iron rings. Early in the eighties he began to work in conjunction with a company whose aim was to introduce into London from America the Hallidie system of cable traction, and in 1884 an act of Parliament was obtained authorizing what is now the City & South London Railway-a tube-railway to be worked by cables.
In 1886 Greathead began work to carry the City and South London Railway under the Thames near London Bridge, using a larger version of his shield, with which he bored twin tunnels about 10 feet (3 metres) in diameter. In this project he pioneered the use of compressed air in conjunction with the circular shield. His shield, compressed air, and the cast-iron rings used to line the tunnels came to be adopted generally in tunnel construction. During the progress of the works electrical traction became so far developed as to be superior to cables; the idea of using the latter was therefore abandoned, and when the railway was opened in 1890 it was as an electrical one. Greathead was engaged in two-other important underground lines in London-the Waterloo & City and the Central London. He lived to see the tunnels of the former completed under the Thames, but the latter was scarcely begun at the time of his death.
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James Henry Greathead was a member of the Council of the Institution of Civil Engineers.