Theoretically a steam engine has no limit on the amount of horsepower it can
generate. In practicality the limit is the amount of steam the boiler can
produce. Hence a typical rating for a steam engine was boiler horsepower
rather than draw bar horse power.
--This can go on forever. At speed a steam locomotive can develop tremendous
horsepower and move a lot of tonnage and use just about no water or fuel
doing it. I've ridden steam locomotives at speed with little more than a
spot fire and the cutoff set at perhaps 5 percent or less and we clipped off
mile after mile burning very little fuel and using hardly any water. We also
managed to cook our own meals and make coffee without the need for a
microwave oven or a hot plate.
Diesels doing the same work would be at notch 8 and burning fuel like it was
going out of style.
Doug
