As recorded in The Guinness Book of World Records, the speed of the fastest train is 143.1 m/s. This record is held by the Train a Grand Vitesse (TGV) Atlanique. The train achieved that speed while going from Courtlain to Tours, France on May 18, 1990. The basic purpose of the test program was to push the envelope of the TGV system, and to characterize its behavior at very high speed. A brand new TGV Atlanique train set number 325 (25th of 105 in the Atlanique series) was randomly chosen to be the starting point of the modifications. There was nothing special about this train set, and after the test it was returned to its intended state. Today, the only distinguishing feature on 325, as compared to other Atlanique train sets, is a blue ribbon painted across the nose, and bronze plaques bolted to the sides of the two power cars to commemorate the event.
In preparations for the first round testing, modifications began by shortening the train from its usual 10 trailers to only 4 trailers, resulting in a significant increase in power to weight ratio. Train length was down to 125 m (381 ft.) from 237 m (777 ft.) and weight was down to 300 metric tons from 490 metric tons. So there would not be any electrical problems on the train, mechanics installed semiconductor components (especially thyristors). The main transformers in both cars were replaced by larger models so that they can handle double the usual load. Extensive testing were conducted on the electrical systems. The resulting ratings insured that acceptable heat levels would never be exceeded in testing. Most of the seating in trailer R1 was removed and the space was transformed into a laboratory, to process and record test data on vehicle dynamics, overhead contact and dynamics, tractive effort, aerodynamics, interior comfort and noise, and a host of other parameters.