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

Context paragraphs:
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.

Leaton railway station: Leaton railway station was a minor station located about six miles north of Shrewsbury on the GWR’s Paddington to Birkenhead main line.  Today this is part of the Shrewsbury to Chester line.  It was at the top of the long climb up Hencote bank out of Shrewsbury.  The station opened on 12 October 1848 and closed on 12 September 1960.  The station building (now a private house) can still be seen on the north side of the adjacent Leaton level crossing on the east side of the line.

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.

West Chester University station: West Chester University station is a former railroad station in West Chester, Pennsylvania.  It was a stop on the Pennsylvania Railroad's (PRR) West Chester Line, and later became a part of SEPTA Regional Rail's R3 West Chester line before being closed in 1986.  The West Chester Railroad heritage railway purchased the line, but does not use West Chester University station.

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.

Oldwoods Halt railway station: Oldwoods Halt was a minor station located north of Shrewsbury on the GWR’s Paddington to Birkenhead Woodside 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 of the halt although the area of the adjacent goods siding/s can still be seen on the west side of the line.

Pulford railway station: Pulford was a short-lived minor railway station located on the Great Western Railway's Paddington to Birkenhead line several miles south of Chester, just inside the English border.  The route is still open today as part of the Shrewsbury to Chester Line.  Nothing now remains at the site except for a Pulford AHB level crossing.  The double track on the Wrexham to Chester section was singled in 1983 but was redoubled through here in 2017 as part of a £40 million upgrade of the route.

Haughton Halt railway station: Haughton 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 and would primarily have served the adjacent (and now disused) Haughton Airfield.  Today the route is part of the Shrewsbury to Chester line.  Nothing now remains on the site.

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).

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.

Supporting paragraphs: Shrewsbury–Chester line Thomas Brassey
Answer: 1870