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Crewe Heritage Centre
The Advanced Passenger Train Prototype, universally known as the APT-P, was one of the most ambitious railway projects ever undertaken by British Rail. Officially designated Class 370, it was intended to revolutionise passenger travel on the West Coast Main Line by allowing trains to negotiate curves at much higher speeds without requiring the enormous expense of rebuilding the railway.
Although the APT-P never developed into the production fleet British Rail had envisaged, it was far from a failure in technological terms. Its tilting system, high-speed running, braking technology and traction equipment influenced later British and European trains. The surviving APT-P at Crewe Heritage Centre is therefore an exceptionally important survivor of Britain's attempt to create a genuinely indigenous high-speed railway.
Why British Rail needed the APT
The West Coast Main Line presented a particular problem.
Much of the route between London Euston and Glasgow had been laid out in the nineteenth century and contained numerous curves. Conventional trains could negotiate those curves safely, but their speed was restricted by the lateral forces experienced by passengers.
One solution would have been to rebuild large sections of the railway with straighter alignments and gentler curves. That would have been enormously expensive.
British Rail instead pursued a radically different idea: make the train adapt to the railway.
The solution was active tilting. The passenger-carrying body of the train would tilt inwards as it entered a curve, compensating for the lateral forces experienced by passengers. The train could consequently take curves at substantially higher speeds while maintaining acceptable passenger comfort.
British Rail's own contemporary material described the concept as allowing trains to negotiate curves typically 20–40% faster than conventional trains.
The APT-P was therefore conceived not simply as a faster train but as an alternative to rebuilding the railway itself.
The APT family
The APT-P was the second major stage of a much larger research programme.
The first was the APT-E, the Experimental Advanced Passenger Train. It used gas-turbine power and was primarily a research vehicle. Its work demonstrated that active tilting and high-speed running could be made to work in practice.
The experience gained with APT-E led British Rail to authorise the construction of three pre-production passenger-carrying APT-P trains in October 1974.
The APT-P was a much more ambitious machine than the APT-E. It was an electrically powered train intended specifically for the electrified West Coast Main Line.
The plan was eventually to develop a production version, the APT-S, or Squadron fleet, which would enter regular service in substantial numbers.
That production fleet was never built.
Construction at Derby
The APT-P was constructed by British Rail Engineering Limited at Derby rather than Crewe.
This is an important distinction when discussing the APT-P at Crewe Heritage Centre. Unlike the Class 43s and Class 90s at the museum, the APT-P was not built at Crewe Works. Its vehicles emerged from the Derby works, while Crewe subsequently became one of its principal operating and development bases.
The first APT power car was delivered in June 1977. It was one of six 4,000 hp electric power cars that would ultimately form the traction element of the three prototype trains.
The complete project was technically extraordinary. The power cars used 25 kV AC overhead electricity and were equipped with sophisticated traction equipment, while the passenger vehicles incorporated the tilting mechanism and articulated bogies.
The three APT-P sets were numbered 370001 to 370006, with additional vehicles including spare driving trailers and power cars. In practice, the fleet was sufficiently flexible that different combinations could be assembled for testing.
The APT-P's unusual formation was itself a consequence of its design. A complete train consisted of two seven-car halves coupled back-to-back, with the powered vehicles positioned towards the centre. This produced a fourteen-car train when fully formed.
The remarkable technology
The most famous feature was, of course, the tilting system.
Hydraulic equipment automatically tilted the passenger vehicles into curves. The system was designed to compensate for the lateral acceleration that passengers would otherwise feel.
The APT also introduced sophisticated suspension and braking arrangements.
Its braking system was particularly unusual. The trains employed hydrokinetic braking, using fluid dynamics to absorb enormous quantities of energy without relying solely upon conventional friction brakes.
The train was also designed around advanced articulation and lightweight construction.
The passenger vehicles were largely aluminium-bodied, while the articulated bogies reduced the number of bogies required beneath the train and contributed to its high-speed stability.
British Rail's contemporary publicity described the APT as a major advance in railway technology and envisaged a maximum speed of approximately 155 mph in development, with an initial service speed of 125 mph.
First testing
Testing began before the complete trains existed.
The first power cars were initially hauled by diesel locomotives and tested around Derby. The plan was then to move the electrically powered testing programme to the Crewe area.
British Rail's 1977 announcement specifically anticipated the first live testing of the APT power car in the Crewe area during autumn 1977.
Crewe was an obvious choice.
The town was already one of Britain's principal railway engineering centres, while the surrounding West Coast Main Line provided access to the route for which the APT had been designed.
The APT consequently became a familiar sight around Crewe during the development period.
The speed record
The APT-P's most spectacular achievement came during testing.
On 20 December 1979, an APT-P formation reached 162.2 mph between Quintinshill and Beattock on the West Coast Main Line.
The train was driven by Ernest Rae, with co-driver Wolsley Gilmour.
The achievement established a new British railway speed record.
It was an extraordinary demonstration of what British Rail's engineers had achieved. The APT-P had been designed around a 155 mph development target, yet it exceeded that figure during testing.
The record remained the British railway speed record until 2003, when Eurostar's high-speed testing on the newly constructed High Speed 1 route produced a substantially higher figure.
For a period, therefore, the APT-P was quite literally the fastest train ever to run on Britain's railway.
The problem of introducing a prototype into passenger service
The great difficulty was that the APT-P was still a development train.
It contained numerous experimental systems that had not been subjected to the accumulated experience of a mature production fleet.
British Rail nevertheless came under increasing pressure to demonstrate the train in public service.
The project had suffered delays, while its costs and technical complexity attracted considerable political and press attention.
The intention had been to introduce the APT gradually. Instead, pressure grew to demonstrate what it could do.
That decision would have enormous consequences for the project's public reputation.
The December 1981 passenger service
The first public passenger operation took place on 7 December 1981.
The APT was intended to provide a high-speed service between London Euston and Glasgow Central, exploiting the very characteristics for which it had been designed.
The train achieved an impressive schedule during the inaugural run, completing the journey in approximately four hours and fifteen minutes.
The problem was that the passenger experience did not match the spectacular engineering achievement.
The tilting system produced an unpleasant sensation for some passengers, leading to the notorious press nickname “the Queasy Rider.” Contemporary coverage concentrated heavily on passengers feeling uncomfortable rather than on the remarkable engineering behind the train.
The problem was not simply that the train tilted. The system had been designed to compensate for lateral acceleration, but the relationship between the train's movement, the hydraulic system and the passenger's perception proved more complicated than expected.
The public relations damage was substantial.
The infamous winter failure
The problems became particularly severe during the cold weather of December 1981.
The APT's sophisticated hydrokinetic braking system encountered problems in freezing conditions. Other technical difficulties affected the train, including faults associated with its complex mechanical and hydraulic systems.
The result was disastrous from a publicity standpoint.
The train that had been promoted as Britain's technological future had been placed into public service before its engineers were satisfied that every system was mature.
Contemporary British Rail material subsequently acknowledged that certain prototype features had not proved sufficiently reliable and that further development was required.
The APT was consequently withdrawn from passenger operation.
Why the APT was not simply a technological failure
This is where the conventional story of the APT needs some qualification.
It is often remembered as an expensive British Rail failure that became famous because passengers felt sick.
That is an incomplete interpretation.
The APT project successfully demonstrated several technologies that were subsequently adopted elsewhere.
The basic principle of active tilting worked.
The train demonstrated extremely high speeds on the existing West Coast Main Line.
The 162.2 mph record proved that the underlying high-speed concept was viable.
The project also generated enormous quantities of data about high-speed suspension, wheel/rail interaction, braking, traction and passenger comfort.
The fundamental problem was that British Rail attempted to bring a highly experimental train into public service while several of its systems were still being developed.
The combination of technical complexity, project-management problems, financial pressure and diminishing political support ultimately proved fatal.
Development continued
After the disastrous initial public-service experience, APT-P did not immediately disappear.
British Rail continued to use the trains for testing and development.
By the middle of the 1980s the surviving trains were increasingly being used as development vehicles rather than passenger trains.
The APT programme had effectively lost the political momentum necessary to proceed to the proposed APT-S production fleet.
The planned production trains would have incorporated improvements to many of the systems that had caused difficulties with the prototypes.
That distinction matters. The cancellation of APT-P development did not necessarily demonstrate that the concept itself was impossible. It meant that British Rail was no longer willing or able to finance and manage the next stage.
The end of the APT project
The proposed production APT-S fleet was never constructed.
The APT programme was eventually abandoned, with the remaining prototype vehicles being withdrawn from development work in 1986. Crewe Heritage Centre records 1986 as the year the APT-P was finally withdrawn from service.
The remaining vehicles were dispersed.
Some were scrapped, while others were retained because of their technological significance.
A particularly fortunate group survived at Crewe Electric Traction Depot.
This was the beginning of the APT-P's connection with the Heritage Centre.
The connection with Crewe
Although Derby built the APT-P, Crewe played an important role in its testing and later storage.
The surviving vehicles were eventually gathered at Crewe, where they remained after the end of the development programme.
This was particularly appropriate because Crewe had been one of the principal locations involved in the APT's development and because its railway infrastructure provided direct access to the West Coast Main Line.
The preserved train therefore returned to a place intimately associated with its working life.
Preservation in 1988
The APT-P was withdrawn in 1986.
In 1988, British Rail donated the surviving APT-P to the newly established Crewe Heritage Centre. It became one of the museum's earliest and most important exhibits.
The Centre was itself only established the previous year, as part of the 1987 Crewe Heritage Festival marking 150 years since the railway reached Crewe.
The arrival of the APT was therefore extraordinarily well timed.
The museum was trying to tell the story of Britain's railway technological development, and here was one of the most advanced trains British Rail had ever produced.
Its first location at the Heritage Centre
The APT-P did not initially occupy its present position.
When it arrived in 1988, it was placed on land that subsequently became the site of a supermarket.
When plans for the supermarket were announced in 1990, the train had to be moved.
The surviving APT vehicles were relocated to their present position within the Heritage Centre.
That move was fortunate in retrospect because it established the train in a position where it could remain as one of the Centre's principal exhibits.
The surviving train
The preserved APT-P is not a completely intact fourteen-car train.
What survives is an assembled collection of vehicles representing the original prototype fleet.
Crewe Heritage Centre describes its main APT-P exhibit as the only APT-P preserved, although additional surviving APT-P vehicles have subsequently been reunited with it.
In 2017, the Heritage Centre launched a successful public appeal to acquire another surviving APT-P vehicle that had been displayed at Coventry Railway Museum.
That vehicle was moved to Crewe in March 2018.
The result is that the Heritage Centre now possesses an unusually comprehensive collection of surviving APT-P vehicles.
The significance is enhanced by the fact that many other APT-P vehicles were scrapped during the late 1980s.
The APT and the Pendolino
The most important legacy of the APT-P may actually be found on today's West Coast Main Line.
The tilting technology developed for APT ultimately influenced Fiat's Pendolino programme.
The story is sometimes simplified into “Britain invented tilting trains, gave the technology to the Italians, and bought it back.” The real history is considerably more complicated.
The British research programme demonstrated that high-speed active tilting was viable. Italian engineers subsequently developed their own implementation of tilting technology, incorporating lessons from the British work.
The result was the highly successful Pendolino family.
Eventually, tilting returned to Britain in the form of the Class 390 Pendolinos, introduced for Virgin Trains on the West Coast Main Line.
The irony is extraordinary.
The APT-P had been intended to revolutionise the very railway outside Crewe Heritage Centre.
Decades later, Pendolino trains using related tilting principles became the standard high-speed passenger trains on that same route.
The APT and the Class 91
The APT's influence was not confined to tilting.
Its electric power-car technology also influenced the development of Britain's later Class 91 locomotives.
The Class 91 was developed for the East Coast Main Line's InterCity 225 project. It did not retain APT's active tilting system, but important aspects of its electrical traction technology and high-speed locomotive design were derived from the APT programme.
The APT therefore had a direct technological legacy in two very different directions: its traction technology influenced conventional high-speed electric locomotives, while its tilting technology ultimately influenced modern tilting trains.
The APT's legacy in modern railway technology
The most remarkable thing about the APT is that technologies which appeared exotic in 1981 are now commonplace.
Modern high-speed trains routinely use tilting, sophisticated suspension, computer-controlled traction and advanced braking systems.
The APT-P was attempting to solve all of these problems simultaneously in an era when the necessary electronic control technology was much less mature.
The train was therefore not merely ahead of its time in appearance.
It was attempting to solve problems that remain central to railway engineering today.
The 2002 Pendolino connection
The relationship between APT and the later West Coast railway was highlighted spectacularly on 16 June 2002.
Virgin Trains held an event at Crewe Heritage Centre to launch its new Pendolino fleet.
Pendolino 390006 was positioned alongside the preserved APT-P, creating an extraordinary visual and technological comparison between the original British tilting-train project and its modern descendant.
The Heritage Centre records the event as a formal launch of the new fleet.
The juxtaposition was historically appropriate.
The APT had attempted to achieve faster journey times on the West Coast Main Line by tilting.
The Pendolino was about to do essentially the same thing commercially, using a mature form of tilting technology.
The APT-P at Crewe today
The surviving APT-P is now one of the Heritage Centre's most important exhibits.
Its location is particularly appropriate because the museum sits beside the West Coast Main Line, the railway for which the train was designed.
Visitors can therefore see the prototype alongside the railway on which it was tested.
The train is no longer operational and should not be thought of as a complete working APT set. It is a preserved collection of surviving prototype vehicles, assembled to tell the story of the programme.
The Heritage Centre describes it as the most powerful passenger train to have operated in Britain, and identifies it as the second member of the APT family after the experimental APT-E.
Why the APT-P matters
The APT-P occupies a fascinating position in British railway history because its reputation and its actual achievements are very different things.
It is easy to remember the APT as the train that made passengers feel ill and was subsequently cancelled.
The more complete story is that British Rail attempted something extraordinarily difficult.
It sought to create a train capable of travelling at very high speeds over an existing nineteenth-century railway, without rebuilding the route.
It developed active tilting, advanced braking, articulated vehicles, high-speed bogies and sophisticated electric traction.
It achieved 162.2 mph, establishing a British railway speed record that stood for almost a quarter of a century.
It demonstrated that high-speed tilting could work.
It exposed the engineering difficulties involved in making such a system reliable.
It generated technology and experience that influenced the Class 91 and later tilting trains.
The project failed as a production programme, rather than simply failing as an engineering experiment.
That distinction is crucial.
A remarkable “what if?”
The APT also represents one of Britain's great railway “what ifs”.
Had the project continued, Britain might have introduced a fleet of APT trains during the 1980s, decades before high-speed tilting became commonplace.
Instead, British Rail pursued the more conventional InterCity 225 programme for the East Coast Main Line and later adopted Pendolino technology for the West Coast.
The irony is that the APT's fundamental objective eventually became reality anyway.
Modern Pendolinos now tilt through the curves of the West Coast Main Line.
The journey-time improvements that APT engineers envisaged were eventually delivered by another generation of trains.
The APT therefore did not vanish without trace. Its ideas survived.
Image from '[Principles of Geology ... Reprinted from the sixth English edition, etc.]', 002293153
Author: LYELL, Charles Sir, Bart
Page: 830
Year: 1853
Place: London
Publisher:
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