Unlike the Polhill Railway tunnel through the chalk of the North Downs throughout it's length the surveyors and engineers who produced the Sevenoaks tunnel very accurately encountered severe obstacles in construction. The tunnel which lies a little south of Tubbs Hill station (nowadays Sevenoaks Station) runs north-south for a distance of 1 mile 1693 yards and is on the line to Tonbridge. On completion in 1868 it was the fifth longest railway tunnel in Britain and remains today the thirteenth longest.
The geology of porous rock beds of Greensand ridge Kentish ragstone sands and silt known as hassock ( referred to as assig by the miners) blue clay called "bine" locally was unknown before construction commenced and the volume of water to be encountered proved extremely problematic. There was a further delaying factor in the form of a landowner who was a knowledgeable litigant and the conduct of the engineering gave ample scope for legal claims.
It is interesting to compare the civil engineering work in the same area in the 1960's to construct the Sevenoaks bypass which forms the A21 London-Hastings road which was affected by landslides and water flows from the spring line and porous beds.
Rainfall records only commenced in the 1860's and heavy rainfall during construction on ground with artesian water in difficult geology provided treacherous conditions for the immense construction by the South Eastern Railway Company,
In 1862 Parliament approved a bill which specified that work would be complete within 5 years; I will return to the litigation by one of the landowners who gave permission later.
In late May 1863 construction surveying began the first death is recorded in November 1863 and there are six deaths I have located in burials in the town. In the Riverhead Saint Mary Burial register it is clear that in the absence of a hospital in Sevenoaks the injured were evacuated by train to Guy's Hospital in London and this had the effect of dispersal of fatalities to avoid local newpaper reporting on the progress of construction. Another record worthy of consideration is that the Sevenoaks Pest House was full during construction due to smallpox.Newspaper reports suggest that conditions in the worker huts were spreading contagious diseases although the contractors were anxious to avoid this.
Two strikes hindered work although these appear related to opposition to employment of irish navvies as a local riot against Irish travellers during fruitpicking had taken place. Many of the unskilled workforce employed on the large cutting at the Sevenoaks end of the construction were local agricultural workers unaccustomed to the hard physical labour and dangers of the cutting.
The first death recorded is that of William Leaver aged 17 a local man cause of death drowning in a sump at the foot of a shaft. The Tubbs Hill cutting and portal resulted in many broken bones when local labourers steering wooden barrows were climbing behind a horse gin hawser.In January 1865 a death caused by "flying timber" to a man called Hoare was reported in the local press. In February 1865 John Stevens aged 17 was killed by a fall down a shaft. On 21 August 1866 local press reported an head injury to a man called Basby when a brick fell down a shaft and six men were required to hold him down on the trip to Guy's Hospital London. In August 1868 Henry Garton aged 23 was killed in a tunnel. The fate of "Basby" is unknown and unrecorded and illustrates how injured removed from Sevenoaks may hide the true number of deaths.
Two types of worker were recruited by gangers granted approval by the main contractor. Local Labourers worked above ground and were recruited as they were free from fruit picking and agricultural labour;their work was unskilled and they were particularly at risk of broken limbs and falls in wet conditions especially on cutting sides. Thirteen shafts were numbered from the southernmost end of the tunnel north to Tubbs Hill where a large cutting framed the portal. This cutting longer than most and therefore particularly hazardous during construction.
The shafts were dug by hand with either a horse gin or steam engine (or both in combination) hauling a skip for waste material or water. As the shaft deepened the wooden shuttering would be removed and bricklayers would add brick as the shaft descended. Below ground,miners would prop and use black powder to blast rock and install wooden stages for bricklayers to work along tunnels if water pumps could provide sufficent drainage.
Three brickyards using the "bine" clay from the shafts produced the bricks to be laid.
Water was a constant problem and men would often work waist deep with water entry from above in ten hour shifts night and day to advance the removal of material in their section.
Other skilled workers recruited to work as masons,miners,explosive men,timbermen and outside the tunnels carters,smiths engine drivers ostlers and experienced horse gin operators.
The resulting tunnel is horseshoe shaped with fine stone portals at either end and is a single tunnel designed for two track operation and has 24 feet 8 inches span. The The original ballast was formed by shingle from Dungeness. The water problem forced the bricklayers and surveyor to install metal sheeting behind the brickwork which in places is five bricks deep.
The Lambarde family were one of the most prominent Sevenoaks families and were one of the three Sevenoaks landowners with whom the South Eastern Railway entered into Heads of Management Agreements. William Lambarde was to enter litigation with three grievances which litigation entered Chancery proceedings until a day before the Parliamentry Act clause of five years completion was due; he reached agreement and authorised use of his land. The terms of the financial settlement were not disclosed.
My transcripts of the Parish Registers of Saint Nicholas Parish Church Sevenoaks and Riverhead Saint Mary which contain burials from the Tunnel Construction are now available at Kent Online Parish Clerks website.
© Henry Mantell Downe and Farnborough Online Parish Clerk 2013-2020
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