British Rail Class 91

British Rail Class 91
91111 at King's Cross station, London
Power type	Electric
Builder	BREL Crewe Works
Build date	1988–1991
Total produced	31
Configuration	Bo-Bo
UIC classification	'Bo-Bo'
Gauge	1,435 mm (4 ft 8 1⁄2 in) Standard gauge
Length	63 ft 8 in (19.41 m)
Locomotive weight	81.5 tonnes (80.2 long tons; 89.8 short tons)
Electric system	25 kV AC
Current collection method	Pantograph
Traction motors	GEC G426 (1.175 MW peak/1.135 MW continuous)
Top speed	Design: 140 mph (225 km/h) Service: 125 mph (201 km/h) Blunt-end first: 110 mph (177 km/h)
Power output	6,300 hp (4,700 kW)
Locomotive brakes	Primary, rheostatic (140–30 mph); secondary friction (pneumatic single-cardan shaft-mounted disc and tread brakes; 30–0 mph)
Locomotive brakeforce	45 LTf (450 kN) (21 kN per axle)
Train brakes	Air (axle-mounted triple-disc brakes; 140–0 mph)
Career	East Coast
Number	91001–91031 later 91101–91122, 91124–91132
Axle load class	Route availability 7

The British Rail Class 91 is a class of 140 mph (225 km/h), 6,300 hp (4,700 kW) electric locomotives ordered as a component of the East Coast Main Line modernisation and electrification programme of the late 1980s. The Class 91s were given the auxiliary name of InterCity 225 to indicate their envisaged top speed of 225 km/h (140 mph). The other end of the InterCity 225 train set is formed of a Driving Van Trailer, built with a similar body shell to the Class 91 locomotives. The locomotive body shells are of all-steel construction. Unusually, the motors are body mounted and drive bogie mounted gearboxes via cardan shafts. This reduces the unsprung mass and hence track wear at high speeds. The locomotive also features an under-slung transformer so that the body is relatively empty compared to contemporary electric locomotives. Much of the engineering was derived from the research and operational experience of the APT-P.

History

In 1985, ASEA, Brush and GEC tendered for the design and construction of the Class 91s. GEC subsequently won the bid and the fleet was built by sub-contractors BREL in Crewe between 1988 and 1991. Delivery occurred in two batches, the first 10 then the remaining 21, which were subject to British Rail's acceptance of the initial batch. At the time the Class 91s were branded in British Rail and GEC publicity as the Electra. Derived from power cars of the Advanced Passenger Train, a spare transformer winding to supply power was provided for use on the anticipated West Coast Main Line services in order that suitably equipped Mark 4 T Coaches could tilt, but this was removed during the 'Delta 91' project rebuild (2000 - 2001).^{[citation needed]}

The Class 91s began passenger service on 3 March 1989 when 91001 worked 1P26 17.36 London Kings Cross to Peterborough train. This train was formed of InterCity 125 Mark 3 coaches and a Class 43 power car converted for use as a DVT as the Mark 4 coaches were not yet ready. The Class 91s then began service on King's Cross to Leeds trains on 11 March 1989 when 91008 with a rake of Intercity 125 Mark 3 coaches and power car 43068 worked the 1D32 06:50 Kings Cross to Leeds service. The set then worked 1A12, the 10:00 Leeds to London Kings Cross service. On this service the guard made an announcement whilst descending Stoke Bank that this was the location where Mallard reached its world record speed of 126 mph going down but this morning the Intercity 225 had ascended the bank at 140 mph.

In the early 1990s, after the Treasury failed to provide funding for the InterCity 250, British Rail examined the option of ordering a further set of ten Class 91s to operate on the West Coast Main Line. Limited funding meant that the procurement of the Class 365, Class 465 and Class 466 EMU Networker stock was taken forward instead of these.

91115 running flat end first at London King's Cross

The asymmetric body style is streamlined at one end to allow high speed operation with the fixed sets of Mark 4 coaches in normal push-pull passenger operation. An additional requirement of the design was that they could operate as normal locomotives. This led to a second cab being incorporated into the unstreamlined 'blunt end'; operating with the blunt end first limits the maximum speed of the locomotive to 110 mph (180 km/h) due to aerodynamic stability.

The fleet, previously operated by InterCity and then GNER (Great North Eastern Railway), and National Express East Coast, it is currently run by the nationalised operator East Coast. Since privatisation, the fleet has been owned by HSBC Rail who lease it the operators. Between 2000 and 2003, the whole fleet underwent a refit to improve reliability. This has resulted in the renumbering of the fleet from 910xx to 911xx. During this time, GNER hired in Class 90 locomotives to provide cover.

A Class 91, 91010 (now 91110) holds the British locomotive speed record at 162 mph (261 km/h), set on September 17, 1989, just south of Little Bytham on a test run down Stoke Bank with the DVT leading. Although both Class 370s and Class 373s have run faster, both types are EMUs, which means that the Electra is officially the fastest locomotive in Britain. Another loco, hauling five Mk4s and a DVT on a test run, once ran between London King's Cross and Edinburgh Waverley in 3 hours, 29 minutes and 30 seconds, still the current record. The set covered the route in an average speed of 112.5 mph (181.1 km/h), and reached the full 140 mph (225 km/h) several times during the run. When introduced, they were the most powerful locomotive in Britain before the British Rail Class 92s entered service.

Fleet

Class 91/1, no. 91118 "Bradford Film Festival" at Peterborough on 27 July 2003. This locomotive is painted in GNER blue livery

When British Rail was privatised, the white Intercity livery was progressively removed. New operator GNER applied their corporate livery of blue and red. When GNER lost their franchise in 2007, the red stripe was replaced by white masking tape containing the words National Express and East Coast. National Express East Coast originally planned to repaint all of their InterCity 225 sets in the white and silver NXEC corporate livery within two years. However, the collapse of NXEC in 2009 and its replacement with East Coast saw seen this repainting programme cancelled with only 91111 being the only unit to receive the full National Express livery.

Due to the interim nature of East Coast's franchise it was expected that the whole fleet will remain in its current two liveries (NXEC and the interim GNER livery) until a new franchisee was appointed in 2011 however in June 2010 a new livery of all silver livery with purple stripe was unveiled by East Coast. As of February 2011 units 91101, 91106, 91107 and 91109 currently have this new East Coast livery. Unit 91101 has since been repainted in East Coast Maroon, with Flying Scotsman branding. The most recently painted units are a very similar shade of grey rather than silver, and becomes noticeable when a silver livery is parked next to a grey livery. It is expected that all remaining units are gradually to be repainted in East Coast Silver, so that the next franchise can easily apply their livery to the basic silver.

The Class 91 fleet has carried various nameplates applied in various batches and themes. In the period immediately after repainting into GNER colours in the late 1990s, all locomotives were briefly nameless. Having initially been applied to only a few locomotives in the early 1990s using cast-iron plates, eventually the whole fleet was named, many multiple times, until all were removed in 2008. In 2011, in response to customer requests, East Coast resumed the practice. It began by naming No. 91109 as Sir Bobby Robson with cast-iron plates, unveiled in a ceremony at Newcastle Central Station on 29 March by his widow Elsie and Alan Shearer.

Locomotive number 91023 was involved in both the Hatfield rail crash and the Great Heck rail crash - after refurbishment in 2001 it was renumbered 91132 (rather than 91123).

Subclass	Number built (year)	TOPS number range	Operators	Comments
91/1	31 (1988–1991)	91101–91122 91124–91132	East Coast	Originally classed as 91/0 (91001–91031)

See also

• InterCity (British Rail)
• Class 93

External links

• Dave Coxon, "IC225 and Class 91 commissioning", www.traintesting.com, http://www.traintesting.com/IC225.htm 
• www.thejunction.org.uk, http://www.thejunction.org.uk/flist_91.html Fleet lists: class 91 
• "Running to Time", www.youtube (Channel 4 / Equinox (series)), 1998, http://www.youtube.com/watch?v=VvsIYaRmRAM