British Rail Mark 5 (InterCity 250)

British Rail Mark 5 (Intercity 250)
1:20 Model of Mk 5 coach
In service	Proposed 1994/1995
Number built	None
Formation	9 carriage sets
Capacity	52 / 88 seats - first / standard class per carriage
Operator(s)	InterCity West Coast (Proposed)
Line(s) served	West Coast Main Line (Also see Project Description)
Specifications
Car body construction	Integral Steel or Aluminium monocoque
Car length	26 m (85 ft 4 in) over buffers
Width	2.7 m
Height	Unknown
Doors	Hinged Plug, pneumatically operated
Maximum speed	155 mph (250 km/h)
Weight	c.35 - 42 tonnes
Train heating	Air-Conditioned, Pressure Sealed.
Bogies	Unknown
Braking system(s)	Disc, pneumatically operated
Track gauge	1,435 mm (4 ft 8 1⁄2 in) standard gauge

The British Rail Mark 5 is the designation given to the planned passenger rolling stock for the InterCity 250 project, a plan to improve speeds on the West Coast Main Line that was ultimately scrapped.

The Mark 5 project was intended to produce a new generation of InterCity passenger rolling stock, anticipated for initial use on the West Coast Main Line (WCML), these would have been developed from the Mark 4 stock in service on the East Coast Main Line (ECML). The profile of the InterCity 250 Mark 5 coaches was designed for non-tilting operation unlike the briefly contemplated use of tilting "Mark 4 T" stock on the WCML which is evident in the sloping sides of the Mark 4 coaches.

Following introduction on the WCML, it was suggested that the coaches could have been used as part of later IC250 builds for the East Coast and Great Western Main Lines, replacing the Mark 3 and Mark 4 coaches used in the InterCity 125 and 225s.

Earlier internal studies by British Rail Research in the early 1980s had focussed on the feasibility of developing a successor 25.5m long InterCity coach to the Mark 3 and evaluated the technologies needed to reduce the capital and operating costs by 30%. This was referred to as a Mark 4 coach and targeted a 125 mph operating speed, however the fitting of a Hydrokinetic Brake would provide 155 mph capability

The 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, during 1987 British Rail had considered increasing the length of the Mark 4 to 25.5 m (with 18.13m bogie centres) but the in-service date of 1989 and complexity of changing the design to suit caused the variation order to be shelved.