The Hertford Loop lineQuail Map 2 - England: East [page 24] Feb 1998 (Retrieved 2014-04-12) (also known colloquially as the Hertford Loop) is a branch of the East Coast Main Line, part of the Northern City Line commuter route to London for Hertford and other Hertfordshire towns and an occasional diversion route for the main line. The line is part of the Network Rail Strategic Route 8, SRS 08.03 and is classified as a London and South East Commuter line.
History The line was opened in three stages between 1871 and 1924. The first section called the Enfield Branch Railway was developed by the London and York Railway and went from Wood Green to Enfield.A Regional History of the Railways of Great Britain (Vol. 3 Greater London), H P White, David & Charles Ltd 1971 (Pages 166-7) In 1898, a plan was approved to extend the line north to Hertford and Stevenage, in order to relieve congestion on the main line without having to widen the Digswell Viaduct. Work started in 1905 and Cuffley was reached on 4 April 1910. The construction of two major viaducts and the Ponsbourne Tunnel (at , the longest in the eastern counties of England, the longest on the Great Northern Railway, and the last to be built by traditional methods), combined with World War I shortages of men and materials, delayed the opening of the route to Stevenage until 4 March 1918. Then it was single track and for goods services only. The line finally opened to passengers on 2 June 1924 when a new station at Hertford North was opened.A Regional History of the Railways of Great Britain (Vol. 5 The Eastern Counties), D I Gordon, David & Charles Ltd 1977 (Pages 123-4) The line was electrified in 1977.
The cost of extending the Hertford Loop line to Stevenage was £1.25 million, . The alternative, quadrupling the bottlenecks at Potters Bar and Welwyn, would have been cheaper, but did not come with the increased passenger numbers that the Hertford Loop line would bring.
The line was also used frequently during the Second World War as the Digswell Viaduct was at high risk from bombs.
Route and settlements served The Hertford Loop line leaves the East Coast Main Line at Wood Green South Junction, north of Alexandra Palace. It then serves:
Bowes Park, serving Bowes Park, Bounds Green and Wood Green Palmers Green, serving Palmers Green Winchmore Hill, serving Winchmore Hill Grange Park, serving Grange Park Enfield Chase, serving Enfield Town Gordon Hill, serving Gordon Hill and Forty Hill, also close to Chase Farm Hospital. Crews Hill, serving the village of Crews Hill Cuffley, serving the villages of Cuffley, Northaw and Goffs Oak Bayford, serving the villages of Bayford and Brickendon Hertford North, serving the town of Hertford Watton-at-Stone, serving the village of Watton-at-Stone
The line then rejoins the East Coast Main Line at Langley Junction, just south of Stevenage.
Services Great Northern (part of Greater Thameslink Railway) operates suburban services along the Hertford Loop line between London King's Cross or Moorgate, and Stevenage, Watton-at-Stone or Hertford North. There are also bay platforms at Hertford North, Stevenage, and Gordon Hill, the latter acting as a terminus during peak hours and night only.
Occasionally, London North Eastern Railway, Hull Trains, Grand Central, Lumo, Thameslink and other faster Great Northern services operate non-stop along the route when diverted off the main section of the East Coast Main Line, due to incidents or planned engineering work. There is a reversing siding to the north of Bowes Park which is used to reverse London North Eastern Railway trains heading for Bounds Green Depot.
Infrastructure The line is about long, is double track throughout and is electrified at 25 kV AC using overhead line equipment. It has a loading gauge of W9 and a maximum line speed of .
Grade-separated junctions connect each end of the northbound track with the main line. All stations are long enough to accept two three-car (20m) EMUs. Not all stations are long enough for newly introduced 6-car EMUs, but their walk-through design allows for access.
Tunnels and viaducts Major civil engineering structures on the Hertford Loop line include the following. +Tunnels and viaducts on the Hertford Loop lineRailway StructureLengthDistance from London King's CrossLocationMolewood Tunnel364 yards (333 metres)20 miles 31 chains – 20 miles 14 chainsNorth of Hertford North stationHertford Viaduct14 chains19 miles 15 chains – 19 miles 01 chainsBetween Hertford North and Bayford stationsHornsmill Viaduct (River Lea)6 chains18 miles 58 chains – 18 miles 52 chainsPonsbourne Tunnel1 mile 924 yards (2454 metres)16 miles 21 chains – 14 miles 59 chainsBetween Bayford and Cuffley stationsSopers Farm Viaduct6 chains12 miles 43 chains – 12 miles 37 chainsBetween Cuffley and Crews Hill stationsRendlesham Viaduct7 chains10 miles 40 chains – 10 miles 33 chainsBetween Crews Hill and Gordon Hill stationsDown Enfield Viaduct (Down line)5 miles 22 chainsNorth of Alexandra Palace station
ERTMS trials on the Hertford Loop line Network Rail used Beacon Rail owned Class 313 unit 313121 as a test vehicle for ERTMS on the Hertford Loop line. The plan involved resignalling a section of the double track route to allow existing passenger and freight services to work bi-directionally over the up Hertford Loop line, freeing the down line for ERTMS tests and evaluation.
Future
Takeover by TfL
References
Citations
Sources Hornby, Frank (1995) London Commuter Lines. Volume 1: Main lines north of the Thames. Kettering: Silver Link Publishing Ltd.