This rather unusual air compressor is owned and was restored by my friend Tom Millett.  It was built in 1948 by Ingersoll-Rand and was designed primarily for use by the railroads for track maintenance and repair.  U.S. Patent 2614497 was applied for on Feb. 15, 1947 and issued on Oct. 21, 1952 for this unit.

The design goal was for a light weight portable unit capable of high volume output.  The result was this six cylinder radial unit with three cylinders serving as the gasoline power source and the other three cylinders being the air compressor.  The power cylinders operate with a four stroke cycle and are arranged in an alternating pattern with the compressor cylinders.  In operation, the cylinders are parallel with the ground and the crankshaft is vertical.  There is a relatively large flywheel on the under side with the spokes shaped as fan blades to provide the cooling air.

It is claimed that it would operate four pneumatic tampers simultaneously.

Click on the thumbnails for larger images
Early literature showing original cart for moving it around the job site. Overall view.  The large black item on top is both the fuel tank and the air cleaner.
Overall view - different angle. One power cylinder and one compressor cylinder.  The curved black pipe is the air output manifold.
Pulley for the starting rope. Tom added the mufflers to somewhat tame the harsh exhaust noise.
It uses three terminals of a six cylinder magneto. For contrast, another Ingersoll-Rand compressor.
This is said to be a 100 HP Ingersoll-Rand single cylinder oil engine.  Technology certainly has changed.
Updated 12-01-03
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