Dagny completes construction of the Line ahead of schedule. She and Rearden ride in the engine cab on the Line's first train run, which is a resounding success. Rearden and Dagny have dinner at Ellis Wyatt's home to celebrate. After dinner, Dagny and Rearden make love for the first time. The next day, Rearden is contemptuous of them both for what he considers their low urges, but Dagny is radiantly happy. She rejects Rearden's estimate, knowing that their sexual attraction is based on mutual admiration for each other's noblest qualities.
Dagny and Rearden go on vacation together, driving around the country looking at abandoned factories. At the ruins of the Twentieth Century Motor Company's factory in Wisconsin, they find the remnant of a motor with the potential to change the world. The motor was able to draw static electricity from the atmosphere and convert it to usable energy, but now it is destroyed.
Realizing how much the motor would benefit the transportation industry, Dagny vows to find the inventor. At the same time, she must fight against new proposed legislation. Various economic pressure groups, seeking to cash in on the industrial success of Colorado, want the government to force the successful companies to share their profits. Dagny knows that the legislation would put Wyatt Oil and the other Colorado companies out of business, destroy the Rio Norte Line, and remove the profit she needs to rebuild the rest of the transcontinental rail system, but she's powerless to prevent the legislation.
