Watford DC Line

Watford DC line
378210 at Watford Junction with a service from London Euston.
Overview
Type	Commuter rail, Rapid transit
System	National Rail London Underground
Status	Operational
Locale	Greater London Hertfordshire
Termini	London Euston Watford Junction
Stations	19
Services	2
Operation
Owner	Network Rail
Operator(s)	London Overground London Underground (Bakerloo line)
Depot(s)	Stonebridge Park (LUL) Willesden TMD
Rolling stock	Class 378 "Capitalstar"
Technical
Number of tracks	2
Track gauge	1,435 mm (4 ft 8 1⁄2 in) standard gauge
Electrification	660 V DC third and fourth rail (fourth rail only on sections used by the Bakerloo line)

The Watford DC line is a commuter railway line from London Euston to Watford Junction. Services on the line are operated by London Overground. The line runs beside the West Coast Main Line (WCML) for most of its length. 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 378 "Capitalstar".

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.

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.