Steeple compound engine

The pipe connecting them may be enlarged to form a 'receiver', a reservoir for steam at the intermediate pressure.

A vertical engine could be erected on any reasonably level base that was strong enough to bear its weight.

A horizontal engine required carefully aligned brickwork to support both the crankshaft and cylinder(s) separately.

Fitchburg were notable in also supplying an automatic governor (illus., left-hand flywheel) that controlled the valve's cut-off according to load.

The first 'automatic' governors were termed that because they not only controlled the speed, but could also take over the role of the driver and could vary cut-off too.

The Great Lakes ferry SS Badger continues in service with her original engines.