Hornsey EMU depot and former steam locomotive shed
Initial developments included two road engine sheds, built east of the station (1866) and north of the station. In 1899 a substantial eight road engine shed was built east of the station.
A new train-wash and additional maintenance building for Class 700 units has been constructed on the site of the old Coronation sidings, together with an underframe cleaning building alongside the current shed.
1850 & 1866 GNR engine sheds
A two road dead ended shed was established by the Great Northern Railway (GNR) in 1850, on the east side of the station. The shed closed in 1866 when the nearby Wood Green shed had been built, and was later demolished; making way for expansion of Hornsey station.[map 1]
In 1866 another two road dead ended shed was established ("Wood Green shed"), ~1 km north of the station on the west side of the track adjacent to a new water works, and west of Wood Green common. The shed closed in 1899.[map 2]
1899 GNR eight road engine shed
In 1899 an 8 track shed was constructed to the east of Hornsey station, together with a 52 ft (16 m) turntable, coal stage and water tank; the shed was connected via the Ferme Park sidings.[map 3] The shed provided locos for shunting in the yard and nearby Ferme Park sidings, as well as goods workings across London to the south via Snow Hill tunnel. Hornsey locos shared suburban duties over the southern end of the GNR with locos from Kings Cross Top Shed.
With the passing of steam, in 1961 the shed was converted for use with diesel traction, and continued in use until the early 1970s, closing in May 1971. The shed's duties were passed to nearby Finsbury Park diesel depot.
1973 Great Northern electrification EMU depot
In the 1970s the site was extensively rebuilt; part of the Ferme Park sidings south of the shed were cleared, and a new Electric multiple unit depot constructed;[map 4] the work was done as part of the Great Northern electrification; a new maintenance shed was constructed with six roads, each capable of holding an eight car train. At the same time the old loco shed was converted to use as an Overhead Line (OHL) maintenance depot, stabling an OHL repair train. 
After 1973 the depot code became HE.
In 2008 First Capital Connect opened a 'Driver Training Academy' at the depot in 2008, equipped with British Rail Class 319 and Class 365 driving simulators. The simulators became operational in 2009.
In 2009 Network Rail initiated plans to build a new EMU depot at Hornsey, as part of the Thameslink Programme. After consultations, revised plans for a smaller depot were submitted in 2011. The depot is expected to open in 2016.
Hornsey depot is currently an Electric Multiple Unit depot  for Class 313, Class 365 and Class 387 units. These units are used on the Thameslink and Great Northern Routes, Thameslink units are brought to Hornsey for maintenance tasks such as wheel turning, which Bedford Cauldwell depot is unable to do.
Facilities include a wheel lathe, large maintenance shed with lifting facilities and a train-washing plant, and extensive stabling sidings for Great Northern's commuter stock.
- Network Rail (December 2006). London North Eastern Route Sectional Appendix. Module LN. p. 14 LOR LN101 Seq004. NR30018/02.
- GB Railfreight: vehicle Change proposal - Class 377 Electrostar EMU - Empty movements between existing areas of operation and Hornsey T&RSMD (PDF) (Letter communication), Network Rail, 24 Jan 2011
- London North Eastern Sectional Appendix (PDF), Network Rail, Sep 2013, pp. 84, 116
- TWENTY FOURTH SUPPLEMENTAL AGREEMENT between NETWORK RAIL INFRASTRUCTURE LIMITED and GREAT EASTERN RAILWAY LIMITED (PDF), Office of Rail Regulation, 20 Nov 2003, pp. 17, 80, 98[permanent dead link]
- Thameslink unveils bigger and better Hornsey, Pressreader - Rail, 17 December 2016
- "LONDON - HORNSEY", locosheds.co.uk, retrieved 7 Nov 2013
- Ordnance Survey. 1863. 1:2500, also see 1895 Town Plan, 1:1056 for expansion of Hornsey station.
- "LONDON - WOODGREEN", locosheds.co.uk, retrieved 7 Nov 2013
- Ordnance Survey. 1896. 1:2500, also 1895 Town Plans, 1:1056
- "LONDON - HORNSEY", locosheds.co.uk, retrieved 7 Nov 2013
- Ordnance Survey. 1:2500; 1896, 1914, 1935, 1955.
- Connor, Charlie & Jim (2009). King's Cross to Potters Bar. Midhurst: Middleton Press. p. 79. ISBN 978-1-906008-62-8.
- Drewet, Alan, "BRITISH RAILWAYS EASTERN REGION LOCOMOTIVE DEPOTS 1948-59", glostransporthistory.visit-gloucestershire.co.uk
- "Steam Locomotive Shed - 34B - Hornsey", Rail UK - British Railways 1823 - 2013
- The all-time Guide to UK Shed and Depot Codes (PDF), TheRailwayCentre.Com, 5 May 2005, pp. 6, 12, archived from the original (PDF) on 17 December 2013
- Your NEW Electric Railway - The Great Northern Suburban Electrification, British Rail, May 1973, Maintenance Depots, p.10,
A new maintenance depot to be built at Hornsey will include an inspection shed to accommodate 48 coaches on six lines. All 90 electric multiple-units will be maintained here. Five of the six eight coach long lines [..] will be used for light repairs and interior cleaning [...] The sixth line will have jacking equipment for carrying out heavy repairs [...] The site of the former Hornsey engine depot will be adapted as an overhead line equipment maintenance depot
- Ordnance Survey. 1:10560; 1967-8. 1:10000; 1973-6, 1981-4
- Chaffin, Tom (17 March 2011), First Capital Connect Hornsey Depot (site visit), The Locomotive & Carriage Institution, archived from the original on 13 April 2014
- Performance and Training Academy, and Simulator Centre, officially opened, 27 August 2008, archived from the original on 16 May 2012
- "Depot plan 'will create 550 jobs'", BBC News, 21 July 2009
- NEW PLANS FOR ‘SIGNIFICANTLY SMALLER’ HORNSEY RAIL DEPOT ON DISPLAY, Network Rail, 25 Jan 2011[permanent dead link]
- "VolkerFitzpatrick to build two new train maintenance depots in the UK", www.railway-technology.com, 15 July 2013
- Quail Map 2 - England East [page 14] February 1998 (Retrieved 2014-04-0909)
- Network Rail (March 2016). London North Eastern Route Sectional Appendix (Supplement No 34). Module LN. p. 14 LOR LN101 Seq004. NR30018/02.
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