Scuderi Engine - Wikipedia, the free encyclopedia
This might be along the lines of your thinking Neil.
Most steam engines used either two operational tactics when they evolved.
Multiple cylinders of increasing size that extracted more energy out of the steam like the double , triple and even quadruple expansion types.
The second tactic was to actually shut off the input of steam and allow the expansion to continue to get better efficiency.
The titanic had a turbine and multiple expansion engines because the multiple expansion types were more efficient and economical.
regards
Mech