Yes – I know we have “Pendolino” on the West Coast Main Line, and even tilting diesel units – “Voyagers” on cross-country routes. But why no more examples?
The ability of a train to tilt around curves on rail lines was the much vaunted benefit of the technology, which as well as cutting journey times, could also provide increased capacity on the same routes. Add into the mix, the moving block signalling technology of Level 2 and Level 3 ERTMS, and you have a recipe that could provide a solution to the UK’s apparent capacity problem.
Next year, it will be exactly 20 years since Virgin placed its order for 54 of the Bombardier built trains, with tilting technology supplied by Fiat Ferroviaria. Two decades before that the first tilting trains were seen on British Rail, following significant research and development work, along with pioneering trials with a gas turbine unit. By the end of the 1970s, proposals to revitalise the network had been prepared and the Advanced Passenger Train with its tilting coaches was already on test.
In the 1970s BR spent some time in Germany advertising and promoting APT technology, although the techniques were more successfully adopted and developed in Italy. Ironically, BR’s successful development of the technology meant that the Virgin trains were put to work on the same routes travelled by the APT more than 20 years earlier. Throughout the world, the technology was applied, in a market dominated by European manufacturers, despite the early success in Britain.
In Italy, the heritage can be traced back to 1967 – even before the ‘Jumbo’ jet was rolled out to handle increasing numbers of airline passengers – when Italian State Railways (FS) fitted out its first tilting railcar, the Y0160 – which acquired the nickname “Pendolino”. Following this, and at around the same time as BR was developing the APT, the Italians built the first tilting train, the ETR 401 – it was in fact the first tilting train in the world.
In 1982, FIAT acquired patents for the tilting bogie used on the APT, and combining this with further improvements led to the introduction of the more advanced ETR 450, the first Pendolino to enter regular service in the world. Between 1976 and 1985, much testing and trials were carried out, leading, eventually to the ETR 460, a fleet of 15 tilting trains that entered service on the Milan to Rome route in 1988.
At the same time, sadly, BR had had to abandon its own developments, and the teething problems with the innovative design were never resolved following much negative media coverage, and the lack of political will to invest in Britain’s rail network. This despite the success of the diesel powered HST sets.
The Technology of The Train
There have been two significant development arms for the technology, one driven by ABB, later Adtranz in Sweden, on the X2000 trains for SJ, with the other, of course, Fiat Ferroviaria in Italy.
The principle attributes to rail transport of this technology are:
- Improved passenger travelling comfort
- High speeds on existing tracks
- Low investment costs and environmental impact.
- Flexible operations
- Improved economies on operating expenditure
The X2000 that surfaced in the late 1980s and early 1990s was a 6 coach set, with 1 power car, a driving trailer and four intermediate vehicles, with a maximum design speed of 210 km/hr. This in itself was a 25% increase on existing line speeds, and reduced journey times for the 457 km route from Gothenburg to Stockholm from 4 hours to just under 3 hours.
The vehicles themselves were developed from a mid 1970s project that resulted in self-steering bogies and a car body tilt mechanism, allowing the train to “lean” into curves. Although the softer suspension used on the new bogies reduced track forces and could have enabled the new trains to travel at maximum speeds through curves, without its body tilting mechanism, the level of passenger discomfort would have increased. In order to provide a smoother ride quality at higher speeds, a system of hydraulic cylinders below the vehicle floors allowed the car bodies to tilt at up to 8 degrees, reducing centrifugal forces by up to 70%. To ensure the vehicle bodies tilted to the right degree at the right time, accelerometers in the front driving bogies passed signals to the on-board computer, so that the hydraulic cylinders that activated the body tilt could be accurately controlled. All of the control systems’ main components were duplicated.
The Italian job …
As noted above, the Italian connection has a longer history, tracing its development back to the late 1960s when Fiat Ferroviaria carried out its first experiments with tilting technology. Work continued through the 1970s to improve suspension and tilting mechanisms, to reach the highest standards of safety, comfort and speed. This work resulted in 1985, with an order from Italian State Railways for the ETR450 trains, each of the 15 sets consisting of nine vehicles, delivered in 1988 and set to work between Milan and Rome.
ETR450 was on the outside a more or less conventional fixed formation train, with two driving, power cars and seven intermediate trailers. Only the power cars were fitted with traction motors, whilst the body tilting mechanism was driven by a system of gyroscopes and accelerometers carried in the leading vehicles. The hydraulic cylinders providing the angular rotation were mounted within the body, from floor to cant rail level and connected to a lever mounted across the vehicle, under the floor. The vehicles’ vertical and lateral secondary suspension was provided by “integral flexicoil” springs.
January 1992 saw the arrival of the third generation of “Pendolino”, in the shape of ETR460, with 10 nine-car sets ordered by Italian State Railways (FS), for service on its 3kV DC network. The new “Pendolini” built on the solid foundations established by its predecessors, but took considerable advantage of technological progress, from the power equipment to, of course the tilting technology. With 6MW of power, controlled by chopper inverter based systems, with improvements – technical and aesthetic – to this rapidly advancing high-speed train concept.
The heart of the ETR460 and its active tilting mechanism was the bogie, with a wheelbase of 2.7 metres, limiting the driving forces, even on the sharper curves. The driving and trailing vehicle bogies are interchangeable, except for the driving axles, which of course carry the driving gear, although the motors themselves are fitted to the underside of the vehicles. The suspension includes two stages of horizontal and vertical suspension, together with anti-yaw dampers.
Measurement of almost all aspects of suspension performance is carried out in real time – including the yaw phenomena relies on very sophisticated on-board computers and system management. Unlike its predecessor, the E460 hydraulic actuators for the tilt mechanism are carried below floor levels, just like the Swedish X2000 design.
The only components of the tilting mechanism fixed to the coach body was the transverse locating beam, allowing the body and bogie manufacture to be undertaken separately.
Supporting the weight of the vehicle overall, two groups of coil springs connect the axlebox with the bogie frame and provide the primary suspension, with four pairs of coil springs providing the secondary suspension. Vertical and lateral dampers allow the bogie to move laterally and vertically, along with rotation of the body in relation to the bogie and track. The secondary suspension includes a pair of anti-yaw dampers fitted on either side of the bogie, with their upper ends attached to the body mounted locating beam.
At a time when ‘digital technology’ was still in its infancy, a master computer, or microprocessor, mounted in the driving vehicle obtained input signals from sensors mounted on the leading bogie, controlled the active suspension and tilting mechanism. After processing these signals, the microprocessor calculates the centrifugal acceleration measured by accelerometers and through pneumatic valves, instructs the hydraulic actuators fitted on each bogie to operate.
Slave processor units on the bogies obtained data from the master unit at the head of the train, instructing the hydraulic actuators on that vehicle to rotate or tilt the vehicle body at the appropriate angle according to speed and location on the track. All in all a very sophisticated arrangement, providing for a smooth, comfortable ride for passengers at higher speeds on conventional tracks.
The “Pendolino” technology had also been exported two years prior to the arrival of the E460, to neighbouring Germany. Here, two-car VT610 diesel electric trains, themselves incorporating radically new inverter-induction motor drives, were paired with a 485 kW diesel engine and tilting suspension for service in the Nuremburg area.
Further International Developments ….
It seemed that the tilting train technology was spreading rapidly in the 1980s and 1990s, some example of which are listed below.
Spain – developed a tilting version of its famous “Talgo” articulated trains, with a passive or “natural tilting mechanism”, that has proved highly successful in Spain but has attracted little interest elsewhere.
Germany – following the “conventional” approach for new high-speed lines as pioneered by France, Germany has however progressed the use of tilting technology in the next generation of ICE trains, not surprisingly under the acronym “ICT”. In addition, Adtranz has provided another generation of regional diesel-electric railcars, the VT-611, using the technology developed for the X2000 trains in Sweden. The ICT trains use the “Pendolino” active tilting system.
Italy – the latest generation of ETR460 provides the available option for use on existing tracks, with significant increases in line speeds and journey time reductions.
Finland – Fiat Ferroviaria in partnership with OY Transtech Ltd supplied six-car “Pendolino” type to VR, from 1992. An interesting development offered by the Finnish order, is the likelihood that some of these trains will operate between Helsinki and St Petersburg.
China – A massive market for rail technology, especially perhaps for projects that make effective use of existing infrastructure. Back in 1997, the Adtranz powered X2000 tilting train was ordered by China. The “Xinshisu” as the train is known in China was put to work on Guangzhou-Shenzen-Hong Kong route in the spring of 1998.
Norway – The Adtranz technology built into Sweden’s X2000 trains was applied to the 16 high-speed 3-car emu’s for the Oslo – Gardermoen services.
Portugal – Another success for the Fiat technology, to provide improved line speeds on the Lisbon to Porto route, 10 six-car trains were ordered in the spring of 1996.
Switzerland – Another dual-voltage tilting train was introduced by SBB on services between Italy and Switzerland. Carrying the name “Pendolino Cisalpino”, Fiat Ferroviaria received its order for 9 nine-car units in 1993, with equipment and design derived from the highly successful ETR460 series already proven in service. The tortuous alignments of routes within and through Switzerland would seem to be an obvious application for this technology. The bogie does not feature an active lateral suspension, but did include a new means of ensuring the pantograph is maintained in the correct position to ensure effective current collection. A special frame linking the pantograph, mounted above the vehicle roof, with the tilting beam was activated electro-mechanically, using the same microprocessors used to control the body rotation.
Czech Republic – Quite apart from the likelihood of running the tilting version of ICE trains on international services to Germany and beyond, Czech Railways ordered 10 seven-car trains at the end of 1995. The first of these tilting trains was in service by 2003.
France – very little development of this technology in France, thanks largely to the hugely successful TGV network. Although, in the 1950s a passive tilting mechanism was developed and tested on a Mauzin built railcar. The pursuit of higher speeds in France is dominated by TGV, although SNCF is planning a tilting train to run on existing track. However, ETR460 trains are already running between Lyon and Turin, whilst the French Government are finding it difficult to continue spending huge sums of money on dedicated high-speed lines and will be spending more on TGV, but with tilting technology.
Australia – In Queensland the 622 km Brisbane-Rockhampton line is planning to introduce high-speed services, with tilting technology supplied by Hitachi, supported by Adtranz. The two 6-car trains are to be built by Evans Deakin Industries, with a maximum speed of 160 km/hr, with potential journey time reductions of 30%
USA – The “American Flyer”, for Amtrak’s Northeast Corridor is essentially an update of the Bombardier built Light Rapid Comfortable introduced in both Canada and the USA in the early 1980s. Alstom and Bombardier supplied the trains, with Bombardier building on its previous experience with the LRC trains and supplying the active tilting technology.
The British Connection ….
Back in Britain, it was only after the upgrade to the West Coast Main Line that the technology came into use – but numerous financial problems, and ongoing difficulties with the privatisation of train operation on the UK rail network, and poor public-private partnerships has hampered its development. The first of the Virgin Trains’ Pendolino units made its initial run on February 14 2001, on the Old Dalby test track at Asfordby near Melton Mowbray. Alstom, the power and control systems supplier had bouight the track and was upgrading it with a £12 million investment, which also included ETCS signalling.
Alstom, as GEC-Alsthom purchased the Washwood Heath plant of Metropolitan Cammell in 1989, but sadly the 54 vehicles for the Pendolino units would become the last work done at a plant that was more than a century old. At the end of 2004 the last Pendolino rolled off the production line and, despite attempts to get Alstom to reconsider, the works closed after 158 years of production with the loss of 1900 jobs.
Despite this loss of manufacturing capacity in the UK, Virgin ordered another four trains and 62 cars, which were built between 2009 and 2012 in Italy at the company’s works in Savigliano. Although to be fair to Alstom, they have invested in a brand new technology centre in Widnes in 2017, despite closing the nearby Preston Works.
Britain was a pioneer in innovative rail research back in the 1960s, 70s and early 80s, although it is such a shame we were unable to invest in what is now a global success story.
Britain today is now following the dedicated high-speed lines advocated and built by France and Italy 30 and more years ago. It was announced in December 2017 that Alstom; Bombardier Transportation; Hitachi Rail Europe; Patentes Talgo S.L.U and Siemens will all be invited to tender for a £2.75bn contract to design build and maintain at least 54 trains for the new network. These – except Hitachi – are the same players who were also directly involved with the development of tilting technology. Alstom of course took a 51% stake in Fiat Ferroviaria back in 2000, so Fiat is still in the train making business.
Despite Britain’s pursuit of dedicated high-speed lines through HS2, there is still hope for tilting technology on secondary routes perhaps. This surely offers a more economic way of increasing capacity and availability across the network as a whole – which may not be achieved by HS2 and its extensions.
What a pity we lost so much ability, innovation and capacity in rail technology manufacturing.
APT’s Legacy for the UK: