The following is reproduced from a sheet titled "Class 91 Electric Locomotive for British Rail InterCity".
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The following is reproduced from a sheet titled "Class 91 Electric Locomotive for British Rail InterCity". |
The electrification at 25kV of British Rail's East Coast Main Line requires a new generation of locomotives - the Class 91. Designed for service speeds of 225km/h on existing tracks, the Class 91 displays several unique features along with state-of-the-art technology. These give high levels of utilisation and reliability, with an annual distance run of 420,000 km planned for each locomotive.
During the daytime the Class 91 fleet is used on high-speed InterCity trains. These operate on the push-pull principle, with a Time Division Multiplex system to enable remote control of the locomotive from a Driving Van Trailer. At night other trains can be hauled with either end of the locomotive leading. An assymetric bodyshell design is thus used, styled to minimise aerodynamic resistance at high speeds.
The traction motors are mounted in the locomotive body, with drive to the axles by cardan shafts. This gives a low unsprung mass, whilst the mounting of the main transformer on the locomotive's underframe gives a low centre of gravity. The result is a locomotive giving a very smooth ride and reduced track wear even at high speeds. Microprocessor traction controls are fitted, together with a maintenance diagnostic system. Thyristors are used to give smooth, stepless changes of both traction and dynamic braking current, whilst the use of a radar-based wheel creep control system allows tractive effort to be maximised.
The Class 91 locomotives are supplied by GEC Transportation Projects ltd., with the design and manufacture of bogies and mechanical parts contracted to BREL limited. This teamwork by British industry has resulted in one of the world's most advanced high-performance locomotives, meeting the needs of InterCity well into the 21st century.
| Traffic type: | High speed passenger and freight |
| Description and wheel notation: | Bo-Bo electric locomotive |
| Traction supply: | 25kV ac 50Hz overhead line |
| Length over buffers: | 19400mm |
| Width over bodyside: | 2740mm |
| Roof height (service condition): | 3757mm |
| Bodyshell material: | Monocoque/steel |
| Bogie centres: | 10500mm |
| Bogie wheelbase: | 3350mm |
| Wheel diameter (new): | 1000mm |
| Bogie type: | BREL P7-5A, P7-5B |
| Unsprung mass per axle: | 1.7t |
| Suspension: | Coil and rubber ring primary flexicoil secondary hydraulic damping |
| Min. curve radius (horizontal): | 90m |
| Weight in service condition: | 81.5t |
| Continuous power rating: | 4530kW at 153km/h 3750kW at 225km/h |
| Traction motors: | 4 × GEC G426 of 1132.5kW separately excited body mounted, driving through cardan shafts |
| Control system type: | Microprocessor/GTO thyristor |
| Special features: | Diagnostic system Speed pre-selection facility Radar-based wheel creep control Push-pull control with TDM links |
| Traction system by: | GEC Traction Ltd. |
| Transformer by: | GEC Transformers Ltd. |
| Current collection: | Single arm pantograph |
| Braking system: | Blended rheostatic/air clasp brakes on wheel treads disc brakes on motor armatures |
| Drawgear type: | Side buffers, drophead knuckle couplers |
| Max. speed: | 240km/h |
| Supplied by: | GEC Transportation Projects Ltd. |
| Mechanical parts by: | BREL Limited |
| Erected at: | BREL Limited Crewe Works |
| No. of locos ordered: | 31 |
| Delivery commenced: | February 1988 |
BREL LIMITED, Britain's largest builder and repairer of railway rolling stock, derives its strength from 150 years of experience.
The design and manufacture of vehicles of all kinds is carried out by BREL's New Construction Group, which can offer diesel and electric locomotives of the highest quality, for every application.
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