Replacing horses as a means of power required the carriage to be raised from its traditional position near the ground in order to accommodate the engine and gearing. The engine used high-pressure steam to drive a single cylinder and piston, which in turn powered a crankshaft. The linear motion produced by the piston was converted by the crankshaft into rotational motion and transferred into a spur gear, which turned the axle of the driving wheels. On top of this, the crankshaft powered the engine’s steam cocks, force pump and firebox bellows as well.
Unique to the design was the addition of a forked piston rod, which effectively closed the gap between the piston head and crankshaft. Another innovation was the use of a valve gear, allowing for the carriage’s flywheel to be scaled down, improving both efficiency and the top speed.