London Overground Watford DC Line

London Overground Watford DC Line is a Transport for London operated Overground line in London, England. Running between London Euston and Watford Junction, the London Underground Bakerloo line shares the track of the line from Queen's Park to Harrow & Wealdstone. The London Overground rolling stock used on the line is Class 710 "Aventra".

The "DC" in the title refers to the fact that the line is electrified using direct current. This was done in the early twentieth century with conductor rails (giving compatibility with the London Underground's four-rail system and the contemporary North London Line electrification), hence its name in contrast to the more modern overhead alternating current system on the adjacent WCML.

London Northwestern Railway also runs a fast service between Watford Junction and London Euston along the West Coast Main Line (which runs parallel to the Watford DC Line), calling at Bushey and Harrow & Wealdstone before running non-stop to Euston. The service offers a quicker alternative to the all-stations London Overground service, especially as the operator now accepts TfL's Oystercardticketing. Some peak services to/from Euston are advertised as starting/terminating at South Hampstead or Queens Park or Harrow and Wealdstone in order to persuade passengers to take the frequent faster services.

History
Services on this line began when London and North Western Railway (LNWR) completed the Camden to Watford Junction new line in 1912, to provide additional suburban capacity and more outer-suburban services running non-stop to Euston. It incorporated part of the LNWR Rickmansworth branch (formerly the Watford and Rickmansworth Railway) between Watford Junction and Watford High Street Junction and part of the original slow main line between Queen's Park and South Hampstead stations; two single-track tunnels take the line from South Hampstead to Camden, whence the line reaches Euston station by the main-line tracks. Prior to 1912, at which time the entire route was finally electrified, services were steam operated. Although the operation of the line is mostly self-contained, connections at Watford Junction and Camden allow other trains onto it, a facility used occasionally with trains diverted from the West Coast Main Line should an alternative diversionary route be not available.

The line was operated by British Rail (from 1986 as Network SouthEast) until privatisation. In the Network SouthEast period, it was rebranded as the Harlequin line, after the stations of Harlesden and Queen's Park.

From March 1997 until November 2007, the line was operated by Silverlink. In November 2007 Transport for London (TfL) took full management control of all the intermediate Watford DC line stations as part of the London Overground (LO) service with staffing during opening hours, automatic ticket gates and planned station refurbishment to the standard of the Tube network.

In 1914, LNWR electric units were introduced.

In 1988, Class 313s were introduced.

On 11 November 2007, the route was included in the sale from Silverlink's Wilesden depot to London Overground.

During the partial closure of the North London Line in autumn 2008, London Overground's Monday to Saturday services were diverted away from Euston, running instead via Camden Road onto the North London Line and on to Stratford; the Sunday service was normal.

On 29 July 2009, brand new Class 378 Capitalstars were introduced.

On 13 September 2010, the Class 313s were replaced by brand new Class 378 Capitalstars.

On 14 September 2010, the line was converted to a full Class 378 Capitalstar operation.

On 9 September 2019, brand new Class 710 Aventras were introduced.

Current Route
The Watford DC Line operates via these primary locations.
 * London Euston
 * South Hampstead
 * Kilburn High Road
 * Queens Park
 * Kensal Green
 * Wilesden Junction
 * Harlesden
 * Stonebridge Park
 * Wembley Central
 * North Wembley
 * South Kenton
 * Kenton
 * Harrow and Wealdstone
 * Headstone Lane
 * Hatch End
 * Carpenders Park
 * Bushey
 * Watford High Street
 * Watford Junction