Question: The contractor for the Shrewsbury–Chester line died in what year?

full_context: Document 1: Stretton Aqueduct: Stretton Aqueduct is a short cast iron canal aqueduct between Stretton and Brewood, and near to Belvide Reservoir, in south Staffordshire, England. Designed by Thomas Telford and bearing his name plus its date of construction, 1832, it carries the Shropshire Union Canal (formerly the Birmingham and Liverpool Junction Canal) 30 ft over the A5 road at a skewed angle.
Document 2: Rossett railway station: Rossett was a minor railway station located on the Great Western Railway's Paddington to Birkenhead line several miles north of Wrexham in Wales. The route is still open today as part of the Shrewsbury to Chester Line. Originally, there was a level crossing just north of the platforms but this has been reduced to the status of a foot and cycleway crossing. To the south of the station there were once goods loops on both sides of the line as well as extensive sidings on the east side. Part of the old Up (southbound) platform still survives. The double track on the Wrexham to Chester section was singled in 1983 but has been redoubled between Rossett and Saltney, with work finally completed in April 2017 (a year later than scheduled).
Document 3: History of rail transport in Great Britain: The railway system of Great Britain, the principal territory of the United Kingdom, is the oldest in the world. The system was originally built as a patchwork of local rail links operated by small private railway companies. These isolated links developed during the railway boom of the 1840s into a national network, although still run by dozens of competing companies. Over the course of the 19th and early 20th centuries, these amalgamated or were bought by competitors until only a handful of larger companies remained (see railway mania). The entire network was brought under government control during the First World War and a number of advantages of amalgamation and planning were revealed. However, the government resisted calls for the nationalisation of the network. In 1923, almost all the remaining companies were grouped into the "big four", the Great Western Railway, the London and North Eastern Railway, the London, Midland and Scottish Railway and the Southern Railway. The "Big Four" were joint-stock public companies and they continued to run the railway system until 31 December 1947.
Document 4: Shrewsbury–Chester line: The Shrewsbury–Chester line, also known as the Severn–Dee Mainline (after the rivers on which Shrewsbury and Chester stand), was built in 1846 as the Shrewsbury and Chester Railway. The engineer for the line was Henry Robertson, a partner in locomotive builders Beyer Peacock, while the contractor was Thomas Brassey in partnership with William Mackenzie and Robert Stephenson.
Document 5: Bridgewater Canal: The Bridgewater Canal connects Runcorn, Manchester and Leigh, in North West England. It was commissioned by Francis Egerton, 3rd Duke of Bridgewater, to transport coal from his mines in Worsley to Manchester. It was opened in 1761 from Worsley to Manchester, and later extended from Manchester to Runcorn, and then from Worsley to Leigh.
Document 6: John Whitton: John Whitton (1820, near Wakefield, Yorkshire, England – 20 February 1898), an Anglo–Australian railway engineer, was the Engineer-in-Charge for the New South Wales Railways, serving between 1856 and 1899, considered the Father of New South Wales Railways. Under his supervision, it is estimated that 2171 mi of railway around New South Wales and Victoria were completed. Whitton was responsible for the construction of the Blue Mountains railway line and parts of the Main Western railway line, in particular the Great Zig Zag near Lithgow, and much of the Great Southern line.
Document 7: Thomas Brassey: Thomas Brassey (7 November 1805 – 8 December 1870) was an English civil engineering contractor and manufacturer of building materials who was responsible for building much of the world's railways in the 19th century. By 1847, he had built about one-third of the railways in Britain, and by time of his death in 1870 he had built one in every twenty miles of railway in the world. This included three-quarters of the lines in France, major lines in many other European countries and in Canada, Australia, South America and India. He also built the structures associated with those railways, including docks, bridges, viaducts, stations, tunnels and drainage works.
Document 8: Garabit viaduct: The Garabit Viaduct ("Viaduc de Garabit" in French) is a railway arch bridge spanning the River Truyère near Ruynes-en-Margeride (), Cantal, France, in the mountainous Massif Central region. The bridge was constructed between 1882 and 1884 by Gustave Eiffel, with structural engineering by Maurice Koechlin, and was opened in 1885. It is 565 m in length and has a principal arch of 165 m span.
Document 9: Stanwardine Halt railway station: Stanwardine Halt was a minor station located north of Shrewsbury on the GWR's Paddington to Birkenhead main line. It was opened in the nineteen thirties as part of the GWR's halt construction programme, aimed at combatting growing competition from bus services. Today the route is part of the Shrewsbury to Chester line. Nothing now remains on the site.
Document 10: Roger Morris (engineer): Roger Brian Morris (19 March 1933 – 15 June 2001) was a pioneer in railway engineering, having helped develop the rail system for the Channel Tunnel, the hovertrain project as well as a number of the railway systems in Eastern Europe and South America.
Document 11: Kendal and Windermere Railway: The Kendal and Windermere Railway is a railway in Cumbria in north-west England. It was built as a railway from the Lancaster and Carlisle Railway at Oxenholme via Kendal to near Windermere, opening fully in April 1847. The engineer was Joseph Locke and the partnership of contractors consisted of Thomas Brassey, William Mackenzie, Robert Stephenson and George Heald. It remains open, albeit in much simplified form, as the Windermere Branch Line.
Document 12: Gustave Eiffel: Alexandre Gustave Eiffel (born Bönickhausen; ; ] ; 25 December 1832 – 27 December 1923) was a French civil engineer and architect. A graduate of École Centrale Paris, he made his name with various bridges for the French railway network, most famously the Garabit viaduct. He is best known for the world-famous Eiffel Tower, built for the 1889 Universal Exposition in Paris, and his contribution to building the Statue of Liberty in New York. After his retirement from engineering, Eiffel focused on research into meteorology and aerodynamics, making significant contributions in both fields.
Document 13: Baschurch railway station: Baschurch railway station was a minor station located about ten miles north of Shrewsbury on the GWR’s Paddington to Birkenhead main line. Today this is part of the Shrewsbury to Chester line. The station building (now a private house) can be seen on the west side of the line adjacent Baschurch level crossing; it was designed by Thomas Mainwaring Penson.
Document 14: Shrewsbury Canal: The Shrewsbury Canal (or Shrewsbury and Newport Canal) was a canal in Shropshire, England. Authorised in 1793, the main line from Trench to Shrewsbury was fully open by 1797, but it remained isolated from the rest of the canal network until 1835, when the Birmingham and Liverpool Junction Canal built the Newport Branch from Norbury Junction to a new junction with the Shrewsbury Canal at Wappenshall. After ownership passed to a series of railway companies, the canal was officially abandoned in 1944; many sections have disappeared, though some bridges and other structures can still be found. There is an active campaign to preserve the remnants of the canal and to restore the Norbury to Shrewsbury line to navigation.
Document 15: Thomas Mainwaring Penson: Thomas Mainwaring Penson (1818–64) was an English surveyor and architect. His father and grandfather, who were both named Thomas Penson, were also surveyors and architects. His grandfather Thomas Penson (c. 1760–1824) worked from an office in Wrexham, North Wales, and was responsible for the design of bridges, roads, gaols and buildings in North Wales. His son Thomas Penson (1790–1859) was county surveyor to a number of Welsh counties and also designed bridges. He later moved to Oswestry, Shropshire where he established an architectural practice. Thomas Mainwaring Penson was born in Oswestry, and was educated at Oswestry School. His elder brother was Richard Kyrke Penson who became a partner in the Oswestry practice in 1854, before developing an extensive architectural practice of his own, mainly in South Wales. Thomas Mainwaring Penson trained in his father's practice. Thomas Mainwaring initially designed buildings in the area of the practice, including stations for the Shrewsbury and Chester Railway.
ground_truth: 1870