Pneumatics

thumb|250px|Pneumatic (compressed-air) fireless locomotives like this were often used to haul trains in mines, where steam engines posed a risk of explosion. This one is preserved [[H.K. Porter, Inc. No. 3290 of 1923.]]

air kept under a pressure that is greater than atmospheric pressure

piano that can play prerecorded works on perforated piano rolls

system that propels cylindrical containers through tubes by compressed air

propulsion engine powered by compressed gas

valve that automatically regulates the pressure of fluid traversing it

pneumatic machine component that produces reciprocating linear motion

railway that uses differential air pressure to provide power for propulsion of a railway vehicle

power tool driven by compressed air or carbon dioxide

Refuse & recycling transport system using capsules traveling through vacuum powered tubes.

system of delivery in the capital of the Czech Republic

former demonstration subway line in New York City

toy gun