British Rail Class 43 (HST)

The HST originated in BR's late-1960s search for a successor to loco-hauled expresses on principal British main lines. The Advanced Passenger Train (APT) was the long-term project, but the technical risks of its tilting bogies and gas-turbine power were considerable. As an interim measure, BR developed the High Speed Diesel Train (HSDT) project — a conventional fixed-formation diesel push-pull set capable of 125 mph using proven technology.

The prototype set 252 001 was completed in 1972, comprising two power cars (41001 and 41002, later renumbered 43000/43001) and seven Mark 3 trailer coaches. The prototype set proved successful in trials, including a 1973 record run of 143 mph at Northallerton. Production HSTs followed from 1975, with the first production power cars (43002 onwards) entering service on the Western Region Paddington–Bristol/South Wales route from October 1976. East Coast services followed from 1978, Cross-Country from 1981, and Midland Main Line from 1982.

The streamlined raked-nose front-end was designed by industrial designer Sir Kenneth Grange — the same designer responsible for the Anglepoise lamp, Kodak Instamatic camera, and many other classic British product designs. Grange's HST nose is one of the most celebrated British transport-design icons of the modern era. The Mark 3 trailer coaches were the first British air-suspension passenger stock and the first to use sealed pressure-tight bodies for high-speed running through tunnels.

The HST entered service on the Western Region in October 1976 and progressively replaced loco-hauled expresses on principal British main lines through the late 1970s and early 1980s. The class set a series of world records: in 1973 the prototype reached 143 mph; in 1985 the production fleet reached 144 mph; and on 1 November 1987 power cars 43102 and 43159 set the world diesel speed record of 148 mph (238 km/h) at Northallerton, a record that stands as of 2026.

The HST gave Britain its first regular sub-3-hour London–Edinburgh service (the Flying Scotsman of 1979) and its first sub-2½-hour Paddington–Cardiff service (1976), and was the standard motive power for British inter-city passenger services for over four decades. The original Paxman Valenta engines proved increasingly uneconomic by the early 2000s, and from 2005 most surviving examples were re-engined with the MTU 16V4000 R41R, becoming Class 43/2.

Withdrawals from front-line service began in earnest from 2017 onwards as the Class 800/802 IET (Hitachi-built) progressively took over the Paddington (GWR) and King's Cross (LNER) services. GWR withdrew its principal HST fleet between 2019 and 2023, retaining only a small Devon and Cornwall fleet of shortened five-coach Castle sets. LNER withdrew all HSTs in 2019. CrossCountry still operates a small HST fleet on Edinburgh–Aberdeen and other long-distance routes in 2026, ScotRail's Inter7City fleet of refurbished HSTs operates Scottish inter-city services, and Network Rail's New Measurement Train remains in continuous service.

Many withdrawn HST power cars are preserved or have been earmarked for preservation, and the HST is widely recognised as one of the iconic British train designs.

The unmistakable streamlined raked-nose front-end designed by Sir Kenneth Grange — the most recognisable British diesel locomotive profile of the modern era. The angled cab front-end with the distinctive curving headlight cluster, the smooth aerodynamic flank, and the long flush-sided bodyside are all characteristic. Re-engined Class 43/2 examples are externally identical to original Valenta-engined Class 43s; the difference is the engine note (the MTU sound is significantly different from the Valenta). HST sets always run with two power cars at the ends of the rake of Mark 3 trailer coaches.

41001 (originally HST prototype power car), preserved at the National Railway Museum, York. The HST prototype set 252 001 of 1972 was the proof-of-concept that led to the production HST.

43002, the first production power car, completed at BREL Crewe in 1976. Originally allocated to Old Oak Common for Paddington services; later re-engined and operated by GWR. Earmarked for preservation.

43102, the world diesel speed record holder. On 1 November 1987 power cars 43102 and 43159 set the world diesel speed record at 148 mph (238 km/h) on the East Coast Main Line near Northallerton during a clearance test run for the Class 91 electric introduction. The record stands as of 2026.

43159, the partner power car for the 148 mph record run.

43013, 43014, 43062, etc. — the principal Network Rail New Measurement Train power cars, in continuous front-line service inspecting British infrastructure.

43030, 43040, 43076, etc. — among the GWR Castle Class HST fleet operating Devon and Cornwall services in 2026.

43170, 43171, etc. — among the ScotRail Inter7City fleet.

BR (1976–1996): Original Western Region fleet at Old Oak Common (Paddington–Bristol/South Wales/West of England, 1976 onwards); East Coast Main Line fleet at Bounds Green and Heaton (London–Newcastle/Edinburgh/Aberdeen, 1978 onwards); Midland Main Line fleet at Neville Hill, Leeds (London St Pancras–Sheffield/Nottingham, 1982 onwards); Cross-Country fleet at Plymouth Laira and Bristol (South-West/Birmingham/North-West, 1981 onwards). The HST progressively replaced loco-hauled expresses on all these routes through the late 1970s and early 1980s.

Privatisation onwards (1996–present): Original Western HST fleet passed to First Great Western (later GWR); East Coast HSTs to GNER then National Express East Coast then East Coast then LNER; Cross-Country HSTs to Virgin CrossCountry then the current CrossCountry; Midland Main Line HSTs to Midland Mainline then East Midlands Trains then East Midlands Railway (withdrawn in favour of newer stock). ScotRail acquired a fleet of refurbished HSTs from 2018 for Inter7City services on Edinburgh–Aberdeen and Edinburgh–Inverness. In 2026 ScotRail (Inter7City), CrossCountry, GWR (Devon/Cornwall Castle sets), and Network Rail (New Measurement Train) operate HST fleets.

BR InterCity 125 yellow/blue (1976–1985): the original HST livery — bright yellow nose, dark blue body, with the bold InterCity 125 branding. One of the most striking British train liveries of the 1970s and 1980s.

BR InterCity Executive grey/red (1985–1990): the re-launch InterCity Executive livery of grey body with red and white stripes.

BR InterCity Swallow (1987–1996): the final BR InterCity livery — InterCity "Swallow" branding with the iconic curving "swallow" logo, in dark grey/white/red.

Post-1996 operator liveries: First Great Western dark blue and pink (later GWR Brunswick green); GNER dark blue and gold; National Express East Coast white and silver; East Coast white and red; LNER red; Virgin CrossCountry red and silver; CrossCountry red and grey; Midland Mainline turquoise and orange; East Midlands Trains blue and orange; East Midlands Railway dark grey and orange; ScotRail Inter7City metropolitan blue and white; Network Rail yellow (New Measurement Train).