British Rail Mark 5
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|British Rail Mark 5|
|In service||Proposed 1994/1995|
|Manufacturer||GEC-Alsthom, Bombardier-Prorail or BREL|
|Formation||9 carriage sets|
|Capacity||52 / 88 seats - first / standard class per carriage|
|Operator||InterCity West Coast (Proposed)|
|Line(s) served||West Coast Main Line (Also see Project Description)|
|Car body construction||Fully Integral, monocoque|
|Car length||26 m (85 ft 4 in) over buffers|
|Doors||Hinged Plug, pneumatically operated|
|Maximum speed||155 mph (250 km/h)|
|Weight||c.35 - 42 tonnes|
|Train heating||Air-Conditioned, Pressure Sealed.|
|Braking system(s)||Disc, pneumatically operated|
|Track gauge||1,435 mm (4 ft 8 1⁄2 in) standard gauge|
The British Rail Mark 5 was the designation given to the planned passenger rolling stock for the InterCity 250 project.
The Mark 5 project was intended to produce new rolling stock for the West Coast Main Line, which would be descended from the similar Mark 4 stock in service on the East Coast Main Line. The profile of the Mark 5 coaches was designed for non-tilting operation unlike the briefly contemplated use of tilting "Mark 4 T" stock on the West Coast Main Line which is evident in the sloping sides of the Mark 4 coaches.
The initial intention of InterCity 250 was to build 30 full trains, each consisting of a Class 93 locomotive, nine 26 m long Mark 5 passenger coaches and a Mark 5 Driving Van Trailer. The coaches would be capable of 155 mph (250 km/h) and were specified to be equivalent in weight to the shorter Mark 4 coaches, which were felt to be overweight. The decision to increase the length of the coaches to 26 m from the 23 m of the Mark 4 was dictated by reduced maintenance costs following British Rail studies which indicated that such a length was feasible within the UK loading gauge. Indeed in 1987 British Rail had considered increasing the length of the Mark 4 to 25.5 m but the in-service date of 1989 and complexity of changing the design to suit caused the variation order to be shelved.
The Mark 5 coaches would have been streamlined with powered plug fit doors and potentially fitted with an active suspension system which would help to contribute towards a desired 30% improvement in ride quality compared to the Mark 3 coach - then the benchmark used by InterCity. Development of the Mark 5 rolling stock was accompanied by research into improvements in track quality needed to achieve the desired ride quality at 155 mph. Some of this work was undertaken via computer simulations using the vehicle dynamics software "VAMPIRE" for operation on both the WCML and ECML; this utilised track geometry and ride quality data gathered from Mark 4 rolling stock test runs on the ECML.
The interior of mockups (designed by FM Design, and constructed within marine plywood enclosures at British Rail's Engineering Development Unit, in the Railway Technical Centre, Derby, England during 1991) indicated a 2+2 seating arrangement in standard class (88 seats per coach) with 2+1 in first class (52 seats per coach). The Driving Van Trailer (DVT) would also have come under the Mark 5 project remit. These would have resembled the Class 93 locomotives, with luggage space, a kitchen and a driving cab, similar to those commissioned for the InterCity 225 project.
Creating the Class 93's alone would have cost £380 million. With limited funding after the East Coast Main Line project was completed, the costs were deemed too high, and the project was terminated.
After the InterCity 250 project was scrapped, Virgin Trains, who have operated the West Coast Main Line franchise since the privatisation of British Rail, commissioned new rolling stock in the form of Class 390 electric multiple units—rather than the Class 93 locomotive and separate Mark 5 carriages proposed by British Rail. Current Network Rail track design standards use the Mark 5 coach to represent coaching stock with 19m bogie centres.
- "The Mk 4 and Mk 5 coaches for British Rail Intercity Part 2 : testing, commissioning and service experience with the Mk 4 coach and development of the Mk 5 specification", J A Higton and D R Temple, Proceedings of the Institute of Mechanical Engineers, Vol 206, 1992.
- Designers Journal, Number 67, May 1991.
- "New Age Of Train", Scottish Herald, 13 March 1991.
- Network Rail Track Design Handbook NR/L2/TRK/2049 Issue 12