Class 800

British Rail Class 800 (Hitachi AT300) — the Intercity Express Train

The British Rail Class 800 is the train that arrived to do two very British things at once: modernise inter-city travel, and keep going beyond the wires. Built by Hitachi Rail as part of its AT300 family, the Class 800 is a bi-mode multiple unit—electric under 25 kV overhead lines, diesel on routes (or route sections) where electrification ends. It is best known under two operator brands: Intercity Express Train (IET) on Great Western Railway (GWR) and Azuma on London North Eastern Railway (LNER).

It was procured through the Department for Transport’s Intercity Express Programme (IEP), intended to replace the ageing InterCity 125 (HST) fleets on the Great Western and the InterCity 225 sets on the East Coast. The Class 800 is not a single “iconic train” in the old sense—one locomotive, one rake, one identity. It is a modern fleet platform: units in standard formations, leased and maintained as an industrial system, designed to cover a wide spread of diagrams with the minimum amount of drama.

And in that respect, the Class 800 has been both a success and, at times, a headache. It delivered a step-change in fleet age, passenger facilities, and standardisation. It also entered service with the kind of teething troubles that tend to come with new-build high-speed stock, and later faced significant structural issues that demanded a network-wide engineering response.

What a Class 800 is

A Class 800 is an electro-diesel (bi-mode) trainset with distributed traction. Instead of one big locomotive doing all the work, traction equipment is spread across the set, with powered bogies and motors arranged to provide strong acceleration and stable high-speed running. Under the wires, the train draws power through a pantograph and runs as an electric multiple unit. Away from electrification, it uses onboard diesel generator units to supply electricity to the traction system.

In everyday terms: it is an electric train that can look after itself when the electricity ends.

This bi-mode capability is the key to why the Class 800 was ordered in the first place. Britain’s inter-city routes are not uniformly electrified. The IEP plan assumed partial electrification and the need to run through onto non-electrified sections without changing trains or swapping locomotives.

The IEP context: replacing HSTs and 225s without waiting for full electrification

The InterCity 125 and InterCity 225 fleets were effective, popular in their way, and—by the 2000s—ageing. The HST in particular had proved remarkably durable, but longevity is not the same as being future-proof. Accessibility requirements, emissions expectations, maintenance economics, and passenger expectations for consistent modern facilities all moved on.

The IEP approach was to buy a family of trains that could cover both the Great Western and East Coast needs, built in volume, and supported with a long-term maintenance and availability model. In that sense, the Class 800 is as much a procurement story as an engineering one: a national programme to refresh flagship inter-city fleets with a standard platform.

Manufacturing and supply chain: Japan to County Durham

The Class 800 fleet was built between 2014 and 2018. The bodyshells were produced at Hitachi’s Kasado Works in Japan, then shipped for assembly at Hitachi’s Newton Aycliffe facility in County Durham. This was a significant industrial moment for the UK rail supply chain: Newton Aycliffe was pitched as a modern train-building plant, and the Class 800 programme was central to making that facility viable at scale.

Ownership follows modern UK rolling stock practice: the Class 800 fleets for GWR and LNER are owned by Agility Trains (a consortium formed to deliver the IEP rolling stock) and leased to the operators.

Formations and subclasses: two lengths, several batches

Class 800 units were built in 5-car and 9-car formations, reflecting the different capacity demands and timetable patterns on the two main lines.

The principal subclasses are:

• Class 800/0: 5-car units used by GWR (numbered 800001–800036).
• Class 800/1: 9-car units used by LNER (numbered 800101–800113).
• Class 800/2: 5-car units used by LNER (numbered 800201–800210).
• Class 800/3: 9-car units used by GWR (numbered 800301–800321).

The practical point is simple: the same core design exists in two lengths, with operator-specific interior layouts and performance settings.

Traction and performance: electric when available, diesel when required

Electric operation

Under electrification, the Class 800 runs as an electric multiple unit with modern power electronics and traction motors. This is its best mode in terms of performance and emissions: better acceleration, less noise, and no diesel fuel burn in service.

Diesel operation

On non-electrified sections, the Class 800 uses multiple underfloor diesel generator units. The standard arrangement is:

• 3 diesel engines on a 5-car unit
• 5 diesel engines on a 9-car unit

The engines are typically MTU 12V 1600 series units, configured to provide electrical power to the traction system rather than driving the wheels mechanically. In other words, even in diesel mode it remains fundamentally an electric traction train—just with electricity generated onboard.

Speed

The Class 800 has a typical maximum speed of 125 mph (200 km/h), matching the operating envelope of Britain’s principal inter-city main lines outside the very highest-speed territory. In service, what matters is not just peak speed but how reliably the fleet keeps to high-performance timetables on crowded routes with mixed traffic.

Passenger environment: modern inter-city standardisation

The Class 800 was introduced to provide a consistent, modern inter-city interior compared with the patchwork of refurbished older stock it replaced. Across operators and subclasses, the broad features include:

• air-conditioned saloons
• at-seat power provision (varies by interior fit)
• modern passenger information systems
• accessible toilets and improved accessibility features compared with older fleets
• vestibule and luggage arrangements designed for airport and long-distance flows (notably on GWR’s network)

Layouts differ between GWR and LNER, and between 5-car and 9-car units, with variations in first-class provision, catering spaces, and seat counts. But the basic objective is the same: a standard modern inter-city product that can be deployed widely without the operator needing to manage multiple incompatible train types.

Entry into service: dates and early reality

The Class 800 entered service on the Great Western Main Line on 16 October 2017. The launch was highly visible—and not entirely smooth. Early operation saw teething issues, including well-publicised reliability problems and passenger-environment faults, the sort of thing that tends to happen when a brand-new fleet meets the complexity of the real railway.

LNER’s Class 800 services followed later. The first Class 800s entered service on the East Coast Main Line in May 2019. The delayed introduction reflected the reality of bringing new trains into a busy main line environment: testing, approvals, and technical integration with the signalling and lineside ecosystem can take longer than optimistic plans suggest.

Operational use: where Class 800s run

The two principal operators use the Class 800 on the routes that define modern inter-city Britain:

• GWR operates IETs on long-distance services from London Paddington into the West Country, South Wales, the Cotswolds, and other corridors where electrification is partial or absent.
• LNER operates Azumas on East Coast services where bi-mode operation supports extensions or diversions beyond electrified stretches, and where fleet commonality with related Hitachi types helps standardise inter-city operation.

The depots associated with the fleet reflect this geography. GWR’s support includes sites such as North Pole, Stoke Gifford, and Swansea Maliphant, while LNER’s includes facilities such as Bounds Green, Craigentinny, Doncaster Carr, and Neville Hill.

Reliability and engineering issues: the cracking episode and the response

The Class 800’s history cannot be written honestly without covering the structural cracking issues that affected the wider Hitachi AT300 family in the UK.

In April 2021, GWR withdrew a number of Class 800 sets after cracks were found in areas associated with the bogie-yaw damper arrangements. In May 2021, the situation widened dramatically: multiple operators suspended or reduced use of Class 800-series trains after cracks were identified around lifting points and other structural areas, causing widespread service disruption on key inter-city routes.

The regulator, the Office of Rail and Road (ORR), published detailed findings on the issue (notably in April 2022), describing fatigue cracking and stress corrosion cracking mechanisms in specific aluminium body areas and weld-related features. The mitigation involved inspections, repairs, and engineering modifications—work that is time-consuming, expensive, and operationally painful, but also the reality of maintaining modern lightweight train structures under heavy duty cycles.

The key factual takeaway is that the Class 800 programme faced a serious mid-life engineering challenge, and that the response required coordinated action across operators, maintainers, and regulators. It was not a minor reliability nuisance; it was a fleet-wide engineering issue that temporarily reshaped inter-city service patterns.

The Class 800 in the bigger picture: bi-mode as policy, not just engineering

The Class 800 is sometimes debated as a symbol of a wider question: should Britain have doubled down on electrification instead of buying large bi-mode fleets? That argument sits above the trains themselves. What is unambiguous is that the Class 800 was built to operate in the network Britain had, not the network planners might have preferred.

In operation, the Class 800 has enabled through services across electrification boundaries without locomotive changes, without passengers switching trains, and without timetable compromises that would otherwise be required. It also created a modern, standard inter-city platform that could be procured in volume and maintained with industrial predictability.

At the same time, bi-mode trains carry inherent compromises: diesel engines add weight, complexity, and maintenance burden, especially when running significant mileage under wires where diesel capability is effectively dead weight. The Class 800’s place in railway history will therefore be tied to the electrification choices of the era as much as to its own technical merits.

Summary

The British Rail Class 800 is Hitachi’s bi-mode inter-city fleet built for the UK under the Intercity Express Programme, introduced on GWR in October 2017 and on LNER in May 2019. Built in 5-car and 9-car formations and operated under the IET and Azuma brands, it replaced the HST and InterCity 225 fleets with a modern train capable of running electrically under overhead lines and on diesel power beyond them. Manufactured through a Japan-to-UK assembly pipeline and owned by Agility Trains, it became the standard inter-city platform on two of Britain’s most important main lines. Its service history includes both the expected benefits of fleet modernisation—standardisation, passenger facilities, and operational flexibility—and the hard reality of significant structural cracking issues that required industry-wide engineering action and regulatory scrutiny.