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V150: Power-packed train proves AGV technology in record sprint

01 May 2007

Laurent Charlier describes the record-breaking train that combined TGV and AGV traction technology

JUST 12 minutes and 40 seconds after starting from a standstill at Prény near the eastern end of the completed section of TGV Est Européen, Trainset V150 attained the speed of 574·8 km/h at Kilometre 194 near Eclaires in the Marne département at 13.13.40 on April 3 2007. To be more exact, the speed was 574·79 km/h and the precise location was Km 193·92.

For SNCF, RFF and Alstom, the three partner companies who funded the €30m exploit, this was just the icing on the cake in what is officially known as the French Programme of Excellence in Very High Speed. Significantly, the V150 trainset accumulated several other records, including a series of runs at more than 500 km/h that totalled between 950 and 1 000 km - both before and after the record trip. The last was on April 15.

V150 combines 'the best of what we do', according to Philippe Mellier, President of Alstom Transport. In the two power cars from POS set 4402 were complete sets of traction equipment for operation in France and Luxembourg at 25 kV 50 Hz, at 15 kV 16·7 Hz in Germany and Switzerland, and at 1·5 kV DC in France. Three double-deck vehicles were marshalled between the power cars: two end trailers (R1 and R8) which will eventually be formed into Duplex set 618 and a specially-built centre bar car (R4), which will remain as a test vehicle. On the lower deck of R4 was a complete AGV traction package powering a pair of AGV articulation bogies these were placed between R1 and R4 and between R4 and R8. Trailer bogies were fitted under the outer ends of R1 and R8. 'We wanted to take the opportunity to test the maximum number of components of our high speed technology', said François Lacôte, Technical Director of Alstom Transport and mastermind of the 1990 world speed record.

V150 had been designed to make the record attempt in the westbound direction on TGV Est Européen, running 'wrong line' on a specially-prepared section between Km 264 and Km 170. This was chosen for its favourable profile with a long gentle downgrade and only large radius curves that would not limit the record attempt.

Heading the train was power car M2, followed by R8 which was equipped as a rolling laboratory. On the upper deck were test teams from Agence d'Essai Ferroviaire with specialists monitoring dynamics, braking, traction and current collection, with the test manager's desk at the inner end. The lower deck housed the Alstom test staff and their equipment, the test team for aerodynamics and acoustics and a small rest and relaxation area.

The bar on the upper deck of R4 was laid out with one wall housing a bank of video screens the counter area incorporated materials and features that could be used in future TGV or AGV trainsets . R1 was fitted with 62 first class seats for guests and media, and power car M1 brought up the rear.

Aerodynamics

Numerous modifications were made to reduce air resistance, which at very high speed is responsible for 95% of the resistance to forward movement. Wind tunnel tests were made to determine the optimum air flows, and the measures taken on V150 were calculated to cut resistance to forward movement by 15%.

Power car M2 was fitted with a special 35 mm thick windscreen in an aluminium frame flush with the bodywork, and the windscreen wiper was removed. The leading autocoupler with its opening clamshell cover was also removed and the cover replaced by a single moulding. Wheels with a diameter of 1 092 mm instead of the standard 920 mm were fitted on all bogies along the train, and as this widened the gap between track and train, deeper fairings were attached below the nose and along the bodysides.

Rubber membranes sealed the inter-car gaps along the train, and panels were fitted below the train to ensure a smooth profile and prevent damage from flying ballast. Although bogie fairings were tested, they were not used.

Current collection

The two pantographs on the roof of M2 were removed and panels were inserted to give an uninterrupted profile along the top of the car. On power car M1 at the rear, the pantograph for 15 kV and 1·5 kV DC operation was removed and the space it occupied covered over.

This left the 25 kV pantograph mounted at the front end of M1. It is a Faiveley CX25 design fitted with a single 60 mm wide contact strip designed to handle currents of 700 to 800 A. The pressure exerted on the catenary is controlled automatically by an electronic device that calculates the force needed depending on the speed and the load-bearing capacity of the pantograph, but on V150 'depending on the speed, we adjusted the electronic controls of the pantograph practically in real time', according to Lacôte. The upward force exerted by the pantograph on the contact at 550 km/h wire was calculated to be around 250 N.

The pantograph supplies power directly to the transformer on M1, and three cables were routed along the roofs of the adjoining cars to feed the other traction equipment: a 25 kV link to M2, a separate 25 kV link to the AGV traction package on R4 and a 1·5 kV DC link for auxiliaries.

The transmission ratios on the power bogies were altered to give a speed of 114·2 km/h at 1 000 rev/min on M1 and M2 and 116·7 km/h at 1 000 rev/min on the AGV bogies. Additional anti-yaw dampers were fitted on all the bogies.

Traction equipment

The asynchronous traction motors on M1 and M2 which have a nominal rating of 1 250 kW were uprated to 1 950 kW. The AGV permanent magnet synchronous motors normally rated at 720 kW were uprated to 1 000 kW, giving a total power output of 19·6 MW. The POS motors are suspended from the vehicle frame, but the smaller AGV motors are mounted in the bogie frames, allowing the tripod transmission used on previous designs of TGV to be abandoned in favour of a simpler and lighter mechanism (Fig 4).

The POS traction equipment with 3·3 kV IGBTs and individual control of traction motors was described in RG 12.06 (p783). A Tornad onboard train management system ensures compatibility with TGV Duplex, Réseau and PBKA trainsets, and no difficulty was encountered in matching it to the V150 configuration.

The AGV equipment in R4 consisted of a centrally mounted transformer and a traction block at each end each block has two inverters, one for each traction motor. IGBTs rated at 6·5 kV are used to feed an intermediate 3 kV DC bus - an arrangement similar to that developed for the four-system Prima 6000 freight locos for SNCF. As the AGV traction control relies on more recent technology than that in the POS power cars, commands had to be passed through an entry/exit interface module in each driving cab. A multiple vehicle bus transmitted commands and data to and from the AGV traction equipment.

Assembly

Launched in October 2005, the V150 programme saw assembly of R4 commence in January 2006 at the Alstom plant in Aytré near La Rochelle. The two POS power cars emerged from the company's Belfort factory in July 2006 after which they were sent to the SNCF's workshops at Bischheim to be modified for the record attempt. Cars R1 and R8 were produced at Reichshoffen, with bogies being made at Le Creusot. Ornans produced the traction motors with other traction equipment being sourced from Tarbes and electronic control devices from Villeurbanne.

Detailed studies for the V150 project were carried out by SNCF's rolling stock engineering centre in Le Mans, and Agence d'Essai Ferroviaire based at Vitry-sur-Seine was responsible for testing.

Once the power cars had been modified at Bischheim they travelled to Aytré to be married to the three centre cars. The five-car formation had its first outing on December 17 2006, and three days later it reached the Technicentre Est Européen at Pantin-Bobigny just outside Paris which was to become its home for the duration of the tests and the record attempt. The first run on TGV Est took place on January 15, with a series of tests following over the next six weeks.

Speed was gradually increased to over 400 km/h, and 40 runs were made when speeds exceeded 450 km/h. A total of 200 hours of running tests accumulating 3 200 km yielded a mass of valuable data with 800 different parameters being measured, of which 500 were on board V150.

The research and test teams monitored braking performance, energy consumption, noise, aerodynamics, dynamic behaviour, vibrations, track-train interaction, current collection and ballast uplift and much more.

Early conclusions showed that aerodynamic phenomena became extremely significant between 500 and 550 km/h. Alstom was pleased with 'the good comfort levels in the Duplex cars across the whole speed range' and noted 'the excellent dynamic performance of the AGV motor bogies which had never turned a wheel before'.

Of particular interest was the use of emergency brakes to halt the train from a speed of 506·8 km/h on March 28 after a device protecting an extensometer used to measure metal strain in a wheel became detached. With the help of the four discs on each axle of the two trailer bogies, the train halted after 16·8 km - compared with an estimate of 25 km. The discs reached a temperature of 650°C.

  • CAPTION: The AGV bogies were mounted between cars R8 and R4 and between cars R4 and R1
  • CAPTION: The electronically controlled Faiveley CX 25 pantograph has a single 60 mm wide collection strip
  • Fig 2. Traction-speed graph for V150, showing the separate outputs from the POS and AGV traction packages
  • Fig 3. Six of the eight bogies of trainset V150 are motored, giving an exceptional power to weight ratio. Vehicle R8 was configured as a laboratory for the AEF and Alstom test teams
  • Fig 4. The AGV power bogie has permanent magnet traction motors attached to the bogie frame, avoiding the need for the complex tripod transmission used on TGV trainsets