Live steam is steam

Steam

Steam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...

 under pressure, obtained by heating water in a boiler

Boiler

A boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications.-Materials:...

. The steam is used to operate stationary or moving equipment.

A live steam machine or device is one powered by steam, but the term is usually reserved for those that are replica

Replica

A replica is a copy closely resembling the original concerning its shape and appearance. An inverted replica complements the original by filling its gaps. It can be a copy used for historical purposes, such as being placed in a museum. Sometimes the original never existed. For example, Difference...

s, scale model

Scale model

A scale model is a physical model, a representation or copy of an object that is larger or smaller than the actual size of the object, which seeks to maintain the relative proportions of the physical size of the original object. Very often the scale model is used as a guide to making the object in...

s, toy

Toy

A toy is any object that can be used for play. Toys are associated commonly with children and pets. Playing with toys is often thought to be an enjoyable means of training the young for life in human society. Different materials are used to make toys enjoyable and cuddly to both young and old...

s, or otherwise used for heritage

Cultural heritage

Cultural heritage is the legacy of physical artifacts and intangible attributes of a group or society that are inherited from past generations, maintained in the present and bestowed for the benefit of future generations...

, museum, entertainment, or recreational purposes, to distinguish them from similar devices powered by electricity or some other more convenient method but designed to look as if they are steam-powered.