The pneumatic motor was unique. Instead of having the conventional folding pneumatics, the crank shaft was propelled by linkage going to six giant pouches which would sink into the hollowed-out cavity when the distributor valves on the opposite side of the motor body connected to vacuum. The stack has unit valve blocks in three rows* and secured with two wood screws (see gasket no. 1234). The front of this valve block was faced with bellows cloth.
*Very early models, around 1910, had four rows of the unit valve blocks.

Most of the early models have a double set of tracking pneumatics with two valves in each set. However, the later models have only one tracking pneumatic. Also, very late models have a completely different three-tier stack with individual tiers connected together with large supply tubing. They also have a bleeding tracker as opposed to the earlier valved type.