World record runs by the SNCF on 28/29 March 1955
The world record attempts on 28 and 29 March 1955 which provided SNCF with its DC - electric locomotives BB 9004 and CC 7107 on the route from Bordeaux to Bayonne at 331 km / h was the world speed record for rail vehicles on. In tests in 1954 with an electric locomotive of the CC 7100 series , a top speed of 243 km / h was reached without any problems. The engineers assumed that the theoretically achievable speed would have to be around 320 km / h. For this reason, further research was carried out, as part of which the newWorld record was set.
Locomotives and test trains
The locomotive BB 9004 is a four-axle, electric locomotive of the SNCF, which was manufactured in 1953 by the French manufacturer Jeumont- Schneider . After a mileage of 118,000 km, it was subjected to a general overhaul in order to be prepared for the record attempts afterwards. The CC 7107, on the other hand, is a six-axle locomotive by the French manufacturer Alstom , which was also manufactured in 1953. It was also overhauled before the record runs, with a mileage of 448,000 km.
Today both record locomotives are in the Cité du Train railway museum in Mulhouse .
Technical changes to the vehicles
In order to be able to achieve the desired speeds, the transmission ratio of the drive gears of the BB 9004 was changed from 2.517 to 0.849, and that of the CC 7107 from 2.606 to 1.145. In addition, the spoked wheels of the locomotives were exchanged for wheel disks turned from a steel blank (BB 9004) or forged (CC 7107), because at high speeds a detachment of the wheel tire pressed onto the wheel spider was feared.
The locomotives pulled a test train consisting of three cars , which - like the locomotives - was aerodynamically optimized. For example, the handles, steps and fans on the outer skin were removed and the car transitions were completely closed with bellows , and the end of the last car received an extension to divert the suction. Thus the air resistance of the train could be reduced by around 20%. In order to enable safe braking, locomotives and wagons were fitted with special brake blocks that were able to dissipate very large amounts of heat. To extract the electrical energy from the overhead line , a new pantograph was specially manufactured, which was able to transmit an expected current of around 4000 A without damage. The first two wagons of the train were equipped with a device to divert the current drawn from the overhead line in order to avoid arcing between the wheel and the rail .
Test track
The double-track line from Bordeaux to Hendaye in the Biganos - Morcenx section, electrified in 1927, was chosen for the record runs . With a length of 47 km, this section of the route has only one curve with a radius of 3100 m. The superstructure was in good condition, so that before the record runs, only the ballast in the area of the rail joints was replenished and minor positional errors in the track were corrected.
The overhead contact line consisted of a single contact wire, which sagged a lot due to its high dead weight due to its large cross-section and a mast spacing of 90 m. In order to reduce sagging to a minimum, the test drives had to be carried out at the lowest possible temperature. Finally, the power supply to the overhead line was increased to ensure a decrease in the maximum current of about 4000 A at every point along the route.
Course of the record runs
March 25, 1955 was originally set as the date for the test drives. Since the temperature rose to 28 ° C that day , the contact line sagged so badly that high-speed journeys could not be carried out. It wasn't until the morning of March 27 that it cooled down a bit, so that the BB 9004 was sent on the line with its train. At 276 km / h, however, the test drive was broken off because the running of the pantograph on the overhead line was still not safe enough.
On March 28, the temperature was only 12 ° C, so it was decided to start the record attempts with the CC 7107 locomotive. The train started at 1:25 p.m. from Facture station and reached a world record speed of 326 km / h between route kilometers 67 and 68 before the contact strip of the pantograph melted and broke; the train slowly rolled out. After the journey, the route was examined by SNCF technicians, but no damage to the overhead contact line or superstructure was discovered. Despite the world record achieved, another record run with the BB 9004 was scheduled for the next day.
On the morning of March 29, 1955 around 7:35 a.m. at a temperature of only 5 ° C, the BB 9004 with its test train was again allowed to take off from Facture station. As with the CC 7107, the contact strip broke at around 290 km / h, but the locomotive had a second pantograph that was immediately lifted to the contact wire. With a power of the locomotive of 9,400 kW , a speed of 331 km / h was reached this time at 71.7 km. However, when the driver downshifted the power at this speed, the train began to vibrate heavily. As the investigation of the line showed, the superstructure was deformed over a length of around 500 m because the stability of the locomotive was no longer sufficient.
Since the pantograph of the CC 7107 was damaged and this locomotive, in contrast to the BB 9004, only used one pantograph instead of two, the same speed was specified for both locomotives due to the small speed difference, so that both manufacturers could save face.
From March 24th to April 1st, 2005 the 50th anniversary of the world record was celebrated.
It was not until the beginning of September 2006 that a Taurus III from Siemens broke the world record on the high-speed line from Nuremberg to Ingolstadt with a record of 357 km / h (see world record run on September 2, 2006 ) .
Movie
The film High Speed in Europe , produced by the Deutsche Bundesbahn in 1968, reports in detail about the world record runs in France.
swell
- Rainer Kratochwille: For the benefit of switchable roll dampers in routing elements with variable track curvature . Dissertation, University of Hanover, 2004
- Jörg Schurig: European locomotive ES64U4 sets a world record with 357 km / h . In: Hamburger Blätter der Eisenbahnfreunde Hamburg , issue 3/2007
Web links
F.Nouvion: Compte rendu de ce record écrit par F.Nouvion en 1955. 1955, accessed on May 29, 2016 (French).
Individual evidence
- ^ Announcement celebrating the world speed record of 1955 . In: Eisenbahn-Revue International , issue 6/2005, ISSN 1421-2811 , p. 290.