TGV Atlantique 325

cults3d

On 1 February 1990 at 3.30 p.m., train 325 returned to the Châtillon workshops for a long time. It had then set a new world record at 482.4 km/h on 5 December 1989. The technicians had until 1 March to carry out a new programme of modifications designed to collect new data and achieve a publicity hit of around 500 km/h. This second round of modifications was to take direct advantage of the experience gained in the first phase. The axles of the 24049 and 24050 power cars were removed and sent to the Bischheim workshops in Alsace on 2 February to be fitted with larger 1,090mm wheels. The leading axle of 24049 was fitted with strain gauges and returned to Châtillon 8 days after the other axles on 22 February. Originally, the second axle was also to be fitted with strain gauges, but the deadline of 1 March did not allow time for this. To accommodate the larger wheels, special brake shoes were machined for the brake shoes of the 24049 and 24050 power cars. At 15 mm thick, only two emergency stops were guaranteed. On 6 February the trailers were lifted and the R6 trailer removed from the train set. This brought the 325 trainset to the minimum possible composition since the R4 bar trailer acts as a "keystone" in the articulated design of the TGV. The 325 trainset now weighed 250 tonnes and was 106 m long. From 7 to 14 February, the three remaining trailers underwent further modifications. The 25 kV roof line used to power the lead locomotive was replaced by a simple cable; this made it possible to remove the insulators that supported it between the carriages and that interfered with the air flow. Rubber membranes were fitted to cover the space between the trailers and the Y237B bogies were raised by 40mm. In the gap between power cars and trailers, large fairings were installed. These 'snowploughs', mounted under the couplers, were designed to prevent the formation of a low pressure area between the vehicles, which had caused significant drag in earlier tests. On the power cars, sheet metal shields were fitted to the bogies, and the front fairing was extended downwards by 10 cm to compensate for the larger wheels. Finally, a removable spoiler was fitted to the nose of the 24050 trailing engine. The aerodynamic improvements were supposed to result in a 10% reduction in drag. In the previous test phase, the atmospheric drag force had reached the value of 9 tons at the speed of 460 km/h. On the new version of the 325 trainset, this value was not expected to be reached before 500 km/h. On 27 February 1990, after the two trainsets were coupled, the 325 trainset left the Châtillon workshops for the second time, two days ahead of schedule. This time, it took 2000 hours of work in the workshop to make the modifications. The second test campaign, which culminated in the setting of the world speed record of 515.3 km/h, is summarised in the record timeline below.