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Chat Moss crossing, L&M Railway
Chat Moss, west of Manchester, UK
associated engineer
George Stephenson
date  1826 - 1st January 1830
UK era  Georgian  |  category  Railway  |  reference  SJ696971
ICE reference number  HEW 952
This crossing of Chat Moss was one of the toughest engineering challenges on the Liverpool & Manchester Railway, the world’s first inter-city passenger line. It's a huge swamp of mossy peat, and George Stephenson had to get trains over it safely without the help of modern plant and materials. The line still carries regular services.
The trustees of the Bridgewater Canal (1776) opposed the Liverpool & Manchester Railway, fearing that their lucrative trade route between the cities would face competition. The House of Lords dismissed George Stephenson’s original suggestions for the railway in 1824, finding mistakes in his surveys. Parliament accepted subsequent proposals from George Rennie and his brother John Rennie Jnr (later Sir), with Charles Blacker Vignoles, enacted on 5th May 1826. This second route bisected Chat Moss.
Disagreements over how the project would be run, and the Rennies’ refusal to work with Stephenson, led the railway company to reinstate Stephenson as their engineer. He was convinced that the solution to crossing Chat Moss was to spread the loads over a wide area and distribute the pressure, in effect to form a floating raft on top of the peat upon which to build the railway track bed.
The basin of Chat Moss was formed by glaciation, with layers of glacial tills and gravels over the underlying sandstone. The depression was subsequently filled to overflowing with waterlogged vegetation forming a shallow dome. It covers 2,750 hectares west of Salford and encompasses the individual Chat, Irlam, Barton, Little Woolden, Great Woolden, Bedford and Astley Mosses — the last two are just north of the railway line and were designated a Site of Special Scientific Interest on 29th September 1989. Chat Moss also includes semi-natural woodland and large tracts of farmland, reclaimed from the bog in the 19th century by a network of drainage ditches.
The peat and moss ranges from 4.6m to 11m deep, swelling in wet weather and shrinking in when dry. It was so wet that for every cubic metre of embankment formed, 2.4 cubic metres of raw peat was used (allowing for water to drain when the turf was compressed).
Heather bundles, brushwood mattresses and timber hurdles 2.4-2.7m long and 1.2m wide were placed in layers to form the raft. Botany Bay Wood (SJ730986) was purchased as a source of timber for the work. Ballast, sleepers, chairs and rails were then fixed over the timber base. Old tar barrels were joined end-to-end to make wooden culverts to drain the two parallel side ditches 14.6m apart.
It worked well except at the east end, where progress was negative owing to the quantities of material subsumed by the swamp. Eventually dried peat, dried moss, earth and some cinders were used to stabilise the ground sufficiently. These were used in preference to ballast at locations where the raft kept sinking, as being lighter they enabled it to float more easily.
Conditions for the labourers were difficult. They had to strap planks to their feet to stop themselves sinking into the mire. Though the work had been arduous, the technique used to stabilise Chat Moss was simple and effective, resulting in this section of the railway being the cheapest to construct at £28,000. The whole line was completed for £739,165 — somewhat below the estimate of £796,246.
The Rennies and Vignoles had planned to have a horse-drawn railway, while James Walker and John Rastrick suggested stationary steam engines at fixed locations to haul trains on endless chains. Stephenson maintained that steam locomotives would be faster and more effective. Based on trials at Rainhill in October 1829, Joseph Locke and Robert Stephenson (George's son) demonstrated that Robert’s locomotive Rocket was capable of pulling three times its own weight over the whole length of track — and he won a £500 prize.
The 6.4km long Chat Moss crossing was completed in December 1829 and on New Year’s Day 1830 Rocket was the first train to travel over it. The railway is double track standard gauge throughout its 50km length.
At the inaugural railway journey on 15th September 1830, accident-prone Liverpool MP William Huskisson was knocked down by Rocket (driven by Joseph Locke) as he left his carriage on Northumbrian at Parkside and died later that day. He was the first fatality on a passenger railway.
Full passenger services began on the Liverpool & Manchester Railway on 17th September 1830, with freight services from December. Even now, if you stand near Astley signal box you can feel the ground tremble as a train passes. But modern trains are many times heavier than Georgian ones.
Resident engineers: Jospeh Locke, Mr Allcard, John Dixon, George Meredith, Robert Stannard Snr
Research: ECPK
"Obituary, George Rennie, 1791-1866", ICE Proceedings
Vol.28, pp.610-615, London, January 1869
"The Liverpool & Manchester Railway: Construction", Museum of Science & Industry in Manchester, 2002, available at www.mosi.org.uk
reference sources   CEH NorthBDCE1BRHSmiles3

Chat Moss crossing, L&M Railway