Dollis Brook Viaduct

The official name of the viaduct is taken from Dollis Brook which it crosses. The brook was marked on an 1877 Ordnance Survey map and the name may have originated from a farm called Dollis, previously in Hendon. 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 word dole.{{Cite book|title=A Dictionary of London Place Names|last=Mills|first=A. D. |year=2004|publisher=Oxford University Press|location=Oxford|isbn=0-19-860957-4|page=66}}

The name is not thought to be connected with the area of Dollis Hill, further south. Dollis Hill is thought to mean a "hill associated with a family called Dalley".

{{Main|Edgware, Highgate and London Railway|Northern line}}

The viaduct was designed by John Fowler and Walter Brydone, chief engineer for the Great Northern Railway (GNR) from 1855 to 1861.{{Cite web|url=http://www.ice.org.uk/knowledge/specialist_community_history_PHEW.asp?faculty=&Doctype=&searchString=&whichpage=193 |title=Panel of Historical Engineering Works |publisher=Institution of Civil Engineers |accessdate=21 May 2009 }}{{dead link|date=December 2016 |bot=InternetArchiveBot |fix-attempted=yes }} 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 Edgware, Highgate and London Railway line from Finsbury Park to Edgware, via Finchley and Mill Hill, which was authorised by an Act of Parliament in 1862.{{Cite book|title=Civil Engineering Heritage: London and the Thames Valley|last=Smith|first=Denis|year=2001|via=Institution of Civil Engineers|publisher=Thomas Telford Ltd|location=London|isbn=0-7277-2876-8|pages=167–168}}

File:Dollis Brook Viaduct map.png

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 (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 Northern line.

The start of the Second World War 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.{{Cite book|title=London Railway Atlas |last=Brown |first=Joe |year=2005 |publisher=Ian Allan Publishing |location=Hersham |isbn=0-7110-3137-1 |pages=10–11}}

{{-}}

File:Dollis Brook Viaduct piers.jpg

The viaduct's 13 segmental arches carry it across the valley of the Dollis Brook, and over Dollis Road.{{Cite web|url=http://www.hadleywood.org.uk/images/newsletter_June_07.pdf|title=Hadley Wood News newsletter June 2007|publisher=Hadley Wood News|date=June 2007|accessdate=21 May 2009}}{{dead link|date=September 2017 |bot=InternetArchiveBot |fix-attempted=yes }} Each arch spans {{convert|32|ft|m}} at the springer level, and is based on tapered piers. In each pier there is an opening with an arched soffit 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 {{convert|60|ft|m}}. It is not, however, the highest altitude on the Underground system, which is near Amersham (Metropolitan line) in the Chiltern Hills, at {{convert|150|m|ft}} above sea level.{{Cite web|url=http://www.tfl.gov.uk/corporate/modesoftransport/londonunderground/1608.aspx|title=London Underground Key facts|publisher=Transport for London|accessdate=21 May 2009|url-status=dead|archiveurl=https://web.archive.org/web/20070529041317/http://www.tfl.gov.uk/corporate/modesoftransport/londonunderground/1608.aspx|archivedate=29 May 2007}}

{{Dollis Brook Viaduct location}}

Below the viaduct can be found the Dollis Valley Greenwalk, a long-distance footpath between Moat Mount Open Space in Mill Hill and Hampstead Heath. This is designed to link many green spaces and wildlife corridors along the way and is approximately {{convert|10|mi|km}} long.{{Cite web|url=http://www.times-series.co.uk/news/4296080.Barnet_Council_staff_walk_to_talk/|title=Barnet Council staff walk to talk about the Dollis Valley Green Walk|publisher=Edgware & Mill Hill Times|date=16 April 2009|accessdate=21 May 2009}}{{Cite web|url=http://www.ldwa.org.uk/ldp/members/show_path.php?path_name=Dollis+Valley+Greenwalk|title=Dollis Valley Greenwalk|publisher=The Long Distance Walkers Association|year=2008|accessdate=21 May 2009}} The geology nearby is of London Clay 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 fossils, and these were thought to extend as far northwest as the viaduct.{{Cite journal|last=Walker |first=Henry |date=November 1871 |title=The Glacial Drift at Finchley |journal=Nature |volume=5 |doi=10.1038/005027c0 |pages=27 |issue=106|bibcode=1871Natur...5...27W |s2cid=4038910 |url=https://zenodo.org/record/1429195 |doi-access=free }}

{{Portal|London transport}}

• List of bridges in London

{{Reflist}}

• [http://www.abandonedstations.org.uk/Dollis_Brook_Viaduct.html Pictures of the viaduct]

Category:Buildings and structures in the London Borough of Barnet

Category:Railway viaducts in London

Category:Finchley

Category:Transport infrastructure completed in 1867

Category:19th-century architecture in the United Kingdom