Aboard Train V150, France The speedometer climbed higher and higher - and so did my heart rate.
Inside the last of three double-decker cars sandwiched between two engines, those of us aboard the French bullet train trying to set the speed record on conventional rails watched the digital numbers flash on a screen in kilometers per hour: 400, 450, 500, 550.
Looking out the windows, the French countryside became a green blur.
Then the magic number appeared: 574.8 kph, or 357.2 mph - faster than any humans had ever traveled in a train on rails. As fast as an airplane, but on the ground.
The air pressure made my ears ache.
Frankly, I was happy when it was over - and not because the journey quite literally ended in Champagne.
The chrome and black V150 looked majestic as its engines hummed on the platform near the town of Preny, east of Paris, before Tuesday's record run.
For its mission to break the speed record, the train was modified with a 25,000-horsepower engine, and adjustments also were made to the track, notably the banking on turns. The rails were treated so the wheels could make perfect contact, and electrical power in the overhead cable was increased from 25,000 volts to 31,000 volts.
The V150 was equipped with larger wheels than the normal French TGV - or "train a grande vitesse" - to cover more ground with each rotation, said Alain Cuccaroni, in charge of the technical aspects of testing. French TGVs normally cruise at about 185 mph.
But this was more than a stunt. The demonstration was meant to showcase technology that France wants to sell to multibillion-dollar overseas markets such as China.
China plans to build more than 7,500 miles of high-speed railways in coming years at a cost of more than $250 billion. Construction is to start this year on a high-speed line between Beijing and Shanghai cutting travel time from nine hours to five.
France competes with Germany and Japan for contracts. Earlier Tuesday, Transport Minister Dominique Perben received California Assembly Speaker Fabian Nunez. The state is studying prospects for a high-speed line from Sacramento to San Diego, via San Francisco and Los Angeles.