The Dollis Brook Viaduct, also known as the Dollis Road Viaduct, Dollis Viaduct or Mill Hill Viaduct, is a

railway Rail transport (also known as train transport) is a means of transport using wheeled vehicles running in railway track, tracks, which usually consist of two parallel steel railway track, rails. Rail transport is one of the two primary means of ...

viaduct A viaduct is a specific type of bridge that consists of a series of arches, piers or columns supporting a long elevated railway or road. Typically a viaduct connects two points of roughly equal elevation, allowing direct overpass across a wide ...

to the west of

Finchley Finchley () is a large district of north London, England, in the London Borough of Barnet. north of Charing Cross, nearby districts include: Golders Green, Muswell Hill, Friern Barnet, Whetstone, London, Whetstone, Mill Hill and Hendon. It is ...

North London North London is the northern part of London, England, north of the River Thames and the City of London. It extends from Clerkenwell and Finsbury, on the edge of the City of London financial district, to Greater London's boundary with Hertfordshi ...

, United Kingdom. It carries the

London Underground The London Underground (also known simply as the Underground or as the Tube) is a rapid transit system serving Greater London and some parts of the adjacent home counties of Buckinghamshire, Essex and Hertfordshire in England. The Undergro ...

Northern line The Northern line is a London Underground line that runs between North London and South London. It is printed in black on the Tube map. It carries more passengers per year than any other Underground linearound 340million in 2019making it the bu ...

from Mill Hill East station to Finchley Central station. It is the highest point on the London Underground above ground level, reaching nearly . It is located on a branch that was formerly part of the

Edgware, Highgate and London Railway The Edgware, Highgate and London Railway was a railway in North London, England. The railway was a precursor of parts of London Underground's Northern line and was, in the 1930s, the core of an ambitious expansion plan for that line which was t ...

Etymology

The official name of the viaduct is taken from

Dollis Brook Dollis Brook is a waterway which runs through Barnet in north London. It is a tributary of the River Brent, which is itself a tributary of the River Thames. The Dollis Valley Greenwalk follows almost all of Dollis Brook, apart from a short se ...

which it crosses. The brook was marked on an 1877

Ordnance Survey The Ordnance Survey (OS) is the national mapping agency for Great Britain. The agency's name indicates its original military purpose (see Artillery, ordnance and surveying), which was to map Scotland in the wake of the Jacobite rising of ...

map and the name may have originated from a farm called Dollis, previously in

Hendon Hendon is an urban area in the London Borough of Barnet, northwest London northwest of Charing Cross. Hendon was an ancient Manorialism, manor and parish in the county of Middlesex and a former borough, the Municipal Borough of Hendon; it has ...

. This was earlier named Dalys in 1563, (the) Doles 1574, Dallys 1584 and in its current form of Dollis in 1822. This probably meant "the portions or shares of land (in the common field)", from the

Middle English Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman Conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old English pe ...

word dole. The name is not thought to be connected with the area of

Dollis Hill Dollis Hill is an area in northwest London, which consists of the streets surrounding the Gladstone Park, London, Gladstone Park. It is served by a London Underground station, Dollis Hill tube station, Dollis Hill, on the Jubilee line, providi ...

, further south. Dollis Hill is thought to mean a "hill associated with a family called Dalley".

History

The viaduct was designed by John Fowler and Walter Brydone, chief engineer for the Great Northern Railway (GNR) from 1855 to 1861. The contractor that built the bridge was Smith, Knight & Co. The viaduct came into use on 22 August 1867 with the opening of the GNR's single-track

line from

Finsbury Park Finsbury Park is a public park in Harringay, north London, England. The park lies on the southern-most edge of the London Borough of Haringey. It is in the area formerly covered by the historic parish of Hornsey, succeeded by the Municipal ...

Edgware Edgware () is a suburban town in northwest London. It was an ancient parish in the county of Middlesex east of the ancient Watling Street in what is now the London Borough of Barnet but it is now informally considered to cover a wider area, inc ...

, via

and

Mill Hill Mill Hill is a suburb in the London Borough of Barnet, England. It is situated around northwest of Charing Cross, close to the Hertfordshire border. It was in the Historic counties of England, historic county of Middlesex until 1965, when it b ...

, which was authorised by an Act of Parliament in 1862. Dollis Brook Viaduct map

Although built to carry two tracks, the viaduct initially carried only one. Following the construction of a branch northwards from Finchley to Barnet in 1872, the original Edgware route effectively became a branch of the newer line. In the 1920s, the

London and North Eastern Railway The London and North Eastern Railway (LNER) was the second largest (after London, Midland and Scottish Railway, LMS) of the "Big Four (British railway companies), Big Four" railway companies created by the Railways Act 1921 in Britain. It ope ...

(LNER, successor to the GNR) planned to electrify the line but work was not carried out until the 1930s when the Northern Heights plan led to the doubling and electrification of the lines. This was in preparation for a transfer of the lines to the London Underground for it to form part of the system's

. The start of the

Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

prevented the plans being completed and only the section of the line to Mill Hill East was electrified and reopened in 1941, whilst the High Barnet branch was electrified in 1940. From this point on London Transport trains used only one of the tracks on the Mill Hill branch and the other track was soon lifted. Freight on the line lasted until 1964 when the line west of Mill Hill East was abandoned, leaving the present arrangement.

Length, span and architecture

The viaduct's 13 segmental

arch An arch is a curved vertical structure spanning an open space underneath it. Arches may support the load above them, or they may perform a purely decorative role. As a decorative element, the arch dates back to the 4th millennium BC, but stru ...

es carry it across the valley of the

, and over Dollis Road. Each arch spans at the springer level, and is based on tapered

piers Piers may refer to: * Pier, a raised structure over a body of water * Pier (architecture), an architectural support * Piers (name), a given name and surname (including lists of people with the name) * Piers baronets, two titles, in the baronetages ...

. In each pier there is an opening with an arched

soffit A soffit is an exterior architectural feature, generally the horizontal, aloft underside of the roof edge. Its archetypal form, sometimes incorporating or implying the projection of rafters or trusses over the exterior of supporting walls, is t ...

and a dished invert. The viaduct is made from brick. It is the highest point on both the Northern line and the highest point on the London Underground above ground level, reaching nearly . It is not, however, the highest

altitude Altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum (geodesy), datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometr ...

on the Underground system, which is near

Amersham Amersham ( ) is a market town and civil parish in Buckinghamshire, England, in the Chiltern Hills, northwest of central London, south-east of Aylesbury and north-east of High Wycombe. Amersham is part of the London commuter belt. There ar ...

(

Metropolitan line The Metropolitan line, colloquially known as the Met, is a London Underground line between in the City of London and and in Buckinghamshire, with branches to in Hertfordshire and in London Borough of Hillingdon, Hillingdon. Printed in mage ...

) in the

Chiltern Hills The Chiltern Hills or the Chilterns are a chalk escarpment in southern England, located to the north-west of London, covering across Oxfordshire, Buckinghamshire, Hertfordshire and Bedfordshire; they stretch from Goring-on-Thames in the south- ...

, at above sea level.

Around the viaduct

Below the viaduct can be found the

Dollis Valley Greenwalk The Dollis Valley Greenwalk (or Green Walk) is a footpath route in the London Borough of Barnet in London, England, between Moat Mount Nature Reserve in Mill Hill and Hampstead Heath. The route is designed to act as a link between the Capital Ri ...

, a

long-distance footpath A long-distance trail (or long-distance footpath, track, way, greenway (landscape), greenway) is a longer recreational trail mainly through rural areas used for hiking, backpacking (wilderness), backpacking, cycling, equestrianism or cross-co ...

between Moat Mount Open Space in

and

Hampstead Heath Hampstead Heath is an ancient heath in London, spanning . This grassy public space sits astride a sandy ridge, one of the highest points in London, running from Hampstead to Highgate, which rests on a band of London Clay. The heath is rambling ...

. This is designed to link many green spaces and wildlife corridors along the way and is approximately long. The geology nearby is of

London Clay The London Clay Formation is a Sediment#Shores and shallow seas, marine formation (geology), geological formation of Ypresian (early Eocene Epoch, c. 54-50 million years ago) age which outcrop, crops out in the southeast of England. The London C ...

with small amounts of other rock types. An examination in the late 19th century of the railway cutting between Finchley and Hendon station found a large extent of glacial beds and

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s, and these were thought to extend as far northwest as the viaduct.

References

{{Reflist

External links