Technology in Atlas Shrugged, Ayn Rand's novel includes a variety of technological products and devices. In addition to real world technology (aircraft, automobiles, diesel engines, phonograph records, radios, telephones, television, and traffic signals) Atlas Shrugged also includes various fictional technologies or fictional variants on real inventions.
Fictional technology 
Fictional inventions mentioned in the book include refractor rays (Gulch mirage), Rearden Metal, a sonic death ray ("Project X"), voice activated door locks (Gulch power station), motors powered by static electricity, palm-activated door locks (Galt's NY lab), shale-oil drilling, and a nerve-induction torture machine.
Traffic Signals 
Early on, the book mentions the "screech" of a traffic signal as it changes. This implies the older technology of mechanical traffic signals, the kind which displayed a pennant or flag indicating stop or go, and the inverse indicator in the opposite direction. Traffic signals using lights have been around for over 40 years, so anything of this type is very old compared to today.
Project X 
Project X is an invention of the scientists at the state science institute, requiring tons of Rearden Metal. Basically, it is a "death ray", and is capable of destroying anything with a sonic pulse. The scientists claim that the project will be used to preserve peace and squash rebellion. It is destroyed towards the end of the book, and emits a pulse of radiation that destroys everything in the surrounding area, including Cuffy Meigs and Dr. Stadler, as well as the Taggart Bridge. The invention is publicly introduced as the "Thompson Harmonizer".
Rearden Metal 
Rearden metal is a fictitious metal alloy invented by Hank Rearden. It is lighter than traditional steel but stronger, and is to steel what steel was to iron. It is described as greenish-blue. Among its ingredients are iron and copper.
Initially no one is willing to use Rearden metal because no one wants to stick his neck out and be the first to try it. Finally, Dagny Taggart places an order for Rearden Metal when she needs rails to rebuild the dying Rio Norte Line.
The first thing made from Rearden metal is a bracelet.
Rearden metal is mentioned in sections 114, 121, 131, 148 and 161.
Galt's Motor 
John Galt invented a new type of electrical apparatus described in the book as a motor. However, it does not operate like a motor in the common use of the word today: it is capable of harnessing static electricity and transforming it into useful mechanical work. Its operation is reminiscent of modern speculation about zero-point energy.
Dagny discovers a discarded prototype of the motor and it is superficially described in section Part 1, Chapter 9. Galt shows Dagny the motor and describes it in section Part 3, Chapter 1.
Ferris Persuader 
After all methods of "liberal" persuasion had been performed to try to force John Galt to fix the world (become "Economic Dictator" etc.), Dr. Floyd Ferris was finally permitted to have his way due to the desperate and scattered attitude of Mr. Thompson. Ferris proceeded to take John Galt to his hidden, guarded, laboratory close to the State Science Institute, and wired him to the "Ferris Persuader" - a device filled with dials, knobs and buttons, that presumably shocks its victims as a form of torture. It is said to deliver the maximum amount of pain, but to deliver the least amount of physical damage (so the captive cannot die).
The device fails during its operation on Galt, and neither the trained guard, nor Ferris understand how to fix it. Galt inherently understands, but when Ferris tries to fix it in the manner Galt says, James Taggart's mental breakdown makes Mouch postpone the torture session. Much later, when Dagny Taggart, Francisco D'Anconia, Ragnar Danneskjold and Hank Rearden rescue Galt, Danneskjold dismantles the machine.