GregLocock
Automotive
The compressed air powered locomotive has had a long, if quiet, career. The setup shown above is one of the later and more succesful designs.
I am very interested to know why they reduced the pressure from 150 to 30 atmospheres before using it in the engine. My only thought was that the 30 atm holding tank allowed the air to warm up a bit before hitting the piston, and perhaps 30 atm was as much as they wanted in the engine itself - 450 psi is a fair pressure.
Of course one thing worth pointing out is that they probably weren't worried overmuch about efficiency.
Cheers
Greg Locock
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