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Wraps come off the AGV

03 Mar 2008

Built by Alstom on a speculative basis, the seven-car AGV demonstrator was unveiled to French President Nicolas Sarkozy on February 5. Murray Hughes reports from La Rochelle

A blue curtain lifted to reveal the approaching headlights of France's next generation of high speed train. Loud music boomed and spotlights focused on the dark silhouette of Alstom's Automotrice à Grande Vitesse. Slowly the wedge-shaped nose emerged until the silver and black form was bathed in light.

An unseen locotracteur at the rear brought the train to a stand in front of around 500 guests and journalists who were watching this son et lumière on tiered seating inside Alstom's Bellevue test centre near La Rochelle - and President of France Nicolas Sarkozy sprang into action. The guests, who included Transport Minister Dominique Bussereau, SNCF President Anne-Marie Idrac, and the ambassadors to India and Morocco, were treated to the presidential views on French industrial policy.

Much emphasis was given to Sarkozy's role in rescuing Alstom from possible oblivion in 2004 when, as Minister of Finance, he agreed to the government acquiring a 21% stake in the company. This was sold on in 2006 to the Bouygues industrial group, and Sarkozy felt that the launch of the AGV marked the end of Alstom's revival 'after the terrible crisis of 2004'. Speech over, Sarkozy vanished into the AGV's cab, and guests were allowed to inspect what Alstom's engineers had created.

Distributed power concept

A decade has passed since Alstom first contemplated adding a train with distributed power to its product range. Early research saw two vehicles trialled in the Elisa test train (RG 11.01 p751), and numerous runs on the Lille - Calais section of LGV Nord confirmed that articulation was compatible with distributed power. Indeed, the feature had been pioneered on the original gas turbine powered TGV001 as long ago as 1972.

Looking back, Technical Director of Alstom François Lacôte is almost dismissive of the work done with Elisa. 'Yes, it was a good compromise for the technology available at the time', he says, 'but we needed to go further. We needed a leap into the future - but not into the unknown.' By 2001 Deutsche Bahn was already ordering a second batch of ICE3 trainsets with distributed power from Siemens, and Alstom was more than conscious of the need to catch up with its competitors in the export market for high speed trains. While the double-deck TGV Duplex had proved a success in the domestic market, 'our single-deck TGV was starting to show its age', reflects Lacôte.

A great deal hinged on what happened next. Serious problems with its power station turbines had thrown Alstom into a financial crisis, the severity of which can be judged by Sarkozy's intervention. It was all the more remarkable, therefore, that the company decided to build - in what Lacôte calls the 'darkest hours' - a complete prototype AGV. Around €100m was invested in a development project which covered construction of the seven-car train and the initial phase of testing. It was a courageous move reflecting the company's faith in its own future - and in the capabilities of its engineering team.

Decision vindicated

The decision was amply vindicated when Alstom's first contract for AGVs was announced on January 17 2008. Italian open-access operator Nuovo Trasporto Viaggiatori ordered 25 trains at a cost of €650m, with an option for 10 more (RG 2.08 p68). Not only that, but the deal includes a 30-year maintenance contract for an unspecified figure. According to Lacôte, Alstom did not offer its Duplex design to the Italian operator as only a single-deck train was required; other bidders were Siemens and Bombardier.

Each of NTV's 300 km/h trains will consist of 11 cars, and the fleet will be equipped for operation only at 25 kV 50 Hz and 3 kV DC. With around 500 seats per set, the capital cost per seat works out at €52 000. Assuming 545 seats in each of the Duplex sets ordered by SNCF last year, now known as RGV2N2 (Rame à Grande Vitesse 2 Niveaux 2ème Génération), the price is €48 165, which takes Alstom close to its objective of making the AGV's cost per seat the same as on a Duplex.

Asked about the Italian contract, Lacôte hints at what will be on offer to NTV's customers. Remarking that he is frequently irritated by comments about the plush interiors of Germany's ICE trainsets, he asserts that the NTV trains will be 'superb' as they will benefit from the best of Italian design and styling.

Lacôte says that some components will be fabricated at Alstom's plant at Savigliano in northern Italy, although a statement from NTV suggests that half its fleet will be assembled there. First delivery is scheduled for mid-2010, with NTV set to carry its first passengers on Italy's north-south Alta Velocità corridor in 2011. NTV had planned to unveil details of its trains jointly with Alstom on February 7, but because of the difficulties facing the Italian government, NTV decided at the last minute to postpone its announcement, deeming it 'more correct to present its new business initiative to a fully functional government'.

Permanent magnet motors

Standing in front of the AGV prototype in the Bellevue test centre, Lacôte highlights just what the 'leap into the future' means. Apart from spectacular advances in information technology which 'allow much more information to be processed for the driver', the biggest technical advance is undoubtedly the use of permanent magnet traction motors. There were simply 'too many problems' with this technology when the Elisa cars were built, but rapid progress in 2004-06 gave Alstom the confidence to go ahead.

A complete traction package consisting of four motors, each with its own IGBT-based inverter, plus a transformer and two traction blocks, was installed in the V150 trainset assembled specially for the attempt on the world speed record last year. Numerous trials were carried out at 500 km/h or more, and when on April 3 the V150's speedometer clocked 574·8 km/h it was not just the ultimate test of the AGV traction package (RG 9.07 p548). That run, and the many that preceded it, gave Alstom the opportunity to compare the AGV equipment with the TGV POS power cars on the same train. During the testing process 'we only had pleasant surprises', enthuses Lacôte, describing the fully-sealed permanent magnet motors as 'little gems'.

Georges Palais, who with Lacôte is one of the 'fathers' of the AGV, confirms that each AGV motor has a continuous rating of 760 kW, giving 6 080 kW for the seven-car set. Alstom says that the power per unit of mass in the motor exceeds 1 kW/kg compared with 0·8 kW/kg for earlier designs of motor. Of particular benefit is the compact size, which allows the motors to fit within the bogie frames - although this increases the overall bogie mass by around 10% compared with a TGV, according to Laurent Baron, Head of Alstom's AGV Product Platform. But accommodating the motors in the bogies means that the complex tripod transmission of the TGV can be dropped, bringing advantages in terms of reliability and lower maintenance costs.

The power bogies, which on the prototype are the first, third, sixth and eighth, represent a significant advance, not least through the use of weight-saving high-tensile steel in the frames. Two prototype AGV bogies were fabricated at Le Creusot in early 2007, and just three months later were undergoing ultra-high speed tests as part of the V150 programme. In Lacôte's words, this was 'a dazzling achievement'. He also notes that noise emissions are lower than those from TGV POS power bogies, the sound level being equivalent to that from a trailer bogie. Advances have been made in the design of the AGV's wheels, and Baron predicts that their life will be 15% longer than on a TGV.

The trailer bogies carry three brake discs of newly-developed heat-resistant material on each axle, but the main braking force will normally be applied using blended rheostatic and regenerative braking that can feed up to 8 MW back into the grid.

Another change from the TGV are the slightly shorter bodyshells. These permit an external width of 3 000 mm, with an internal width of 2 750 mm. More interior space is achieved by abandoning the side vents below the windows for the air-conditioning, with the vents relocated to the floor and ceiling. Other changes to the air-conditioning include giving the driver's cab its own climate system; should this fail, the main air-conditioning takes over.

Cab ergonomics

The cab offers a stark contrast with previous TGV cabs. Almost minimalist in design, the cab is reached by a sloping passage between lateral equipment modules. Gone is the traditional French 'steering wheel' used for traction control, and in its place is a small joystick for braking and traction. 'Working with simulators and consulting widely on the ergonomics, we have completely changed the environment for the driver', says Baron. The views of international drivers were sought, and Alstom also fed in the results of the European Driver's Desk research project that was part-funded by the European Commission.

Double-banked headlights make the front end particularly distinctive, and a further headlight is positioned above the windscreen. No less striking are the cab windows, with a central windscreen flanked by an angled pane on each side. According to Baron, these are for aesthetic purposes only, and the driver will look only through the main windscreen. More daylight enters the cab through high-level side windows, and a small window further back can be opened to allow the driver to look back down the train.

Bodyshells are formed of welded aluminium profiles, as on the Duplex trailers; all single-deck TGVs have steel bodies. The AGV's long nose houses an autocoupler as Alstom envisages that up to three sets could run in multiple. In the event of a collision, the coupler and a collapsible element immediately behind it would absorb up to 1·5 MJ of energy. Another structure will concertina to absorb a further 3 MJ, ensuring that there is no deformation of the cab with an impact force of 4·5 MJ. According to Baron, even higher forces were absorbed during tests at Alstom's Reichshoffen plant, while Lacôte confirms that collision-resistance is better than on a TGV Duplex.

Carbon composites

For the first time Alstom has used carbon composites as structural elements on a high speed train. Two of the articulation joints on the prototype incorporate a transverse beam formed of carbon composite material. Fabricated in the shape of a shallow 'U', the beam supports one car end on the secondary suspension. According to Baron, this saves 750 kg compared with a steel structure. However, the 25 AGVs being built for NTV will retain steel for this component.

Aero-acoustic studies led to a decision to fit shrouds over the leading bogies, while rubber fairings close the gaps between cars; these extend across the car at roof level, and the roof offers a smooth profile along the length of the train apart from gaps for the four pantographs; the AC pantographs are to the Faiveley CX design as used on V150. On the demonstrator, these are positioned on the first, second, sixth and seventh cars.

Interior

Seats are fitted in just two vehicles, the other five being reserved for laboratory and test equipment. One car has an economy class layout with 48 seats arranged 2+2, and the other is laid out with 30 seats in a 2+1 format. Alstom is reluctant to give details of its plans for interior designs, but a striking contrast with TGVs is evident when walking through the train. The inter-car gangways on TGVs are only 700 mm wide, but on the AGV redesign of the articulation permits the width of the interior gangway to be increased to 1 000 mm. A walk-through also reveals that the floor is almost level, rising from 1 155 mm above rail top in the saloon to just 1 250 mm over the bogie.

Passenger information and enter-tainment screens are not fitted, as Alstom says 'we know we can do this', pointing out that such items can be fitted later if required. Given that Baron prefers to call the train a demonstrator rather than a prototype, more developments in interior design can be expected - the train is scheduled to be on display at InnoTrans in September this year after spending May to August on the Velim test circuit in the Czech Republic. It will return to France for high speed trials, and there is every prospect of a visit to Italy.

The market

Since the first 30 Duplex sets entered service with SNCF in 1996, the operator has not ordered any single-deck TGVs. Duplex orders to date total 212, and an option for 40 more in the €2·1bn contract for 80 placed last June would take this to 252. Until now SNCF has remained lukewarm towards the AGV, but it is planning a major order for high speed trains later this year, which according to Les Echos could be worth €8bn to €10bn. This is intended to launch the replacement of the Paris - Sud-Est fleet, and speculation is rife that the contract could include an initial batch of AGVs.

Alstom sees the whole of Europe as a potential market for the AGV, and the presence in La Rochelle of Dr Karl-Friedrich Rausch, Board Member for the Passenger business at Deutsche Bahn, follows a presentation that Alstom made to DB on the AGV last July.

Outside Europe, China is frequently mentioned as a target market, but Lacôte is cautious. Although one of his colleagues jokingly admits to looking at a 26-car version of the AGV for China, Lacôte warns that the Chinese invariably demand technology transfer. 'We do not want to give away the technology for the AGV without having a majority holding in the company that receives it', he affirms.

Table I. Main data for Alstom AGV demonstration train

Overall length mm 132 100
Overall length of end car mm 22 800
Distance between bogie centres, centre car to centre car mm 17 300
Bogie wheelbase mm 3 000
Wheel diameter, new mm 920
External width mm 3 000
Internal width mm 2 750
Floor height above rail top mm 1 155
Floor height above rail top over bogie mm 1 250
Weight tonnes 272
Highest static axleload tonnes 17
Continuous power rating kW 8 x 760 = 6 080

Table II. Key dates in the AGV project

1998 First studies carried out
2001 Two research cars built for Elisa test train
2003 Main design features defined
June 2004 Decision to build prototype taken
January 2005 Styling choice made from four designs
November 2005 Mock-up presented at Eurailspeed
July 2006 Design frozen
October 2006 First subassemblies completed
February 2007 First car structure completed
April 3 2007 Power bogies and traction package used on world record speed run
October 2007 Prototype cars turn first wheels at La Rochelle test facility
February 5 2008 Demonstrator unveiled