Additions for Australia by Paul Pavlinovich
Live steam railroading is the term most frequently applied to the branch of the hobby involving larger models, in most cases suitable for hauling (full size) passengers, and in most cases using steam as the propulsion mechanism (hence the name). There are a series of de-facto standard track gauges, and corresponding scales when used to model standard gauge (4' 8 1/2") prototype locomotives:
Gauge 1 (1 3/4" gauge) is also sometimes included in discussions of live steam, even though they are too small to carry passengers. There is still a bit of 2 1/2" gauge (1/24 scale) live steam equipment and track around, which is about the smallest able to pull real passengers. There are also larger sizes, with 12" and 15" gauge being relatively common. There are also a significant number of "odd" sizes in use on private tracks.
The above scales apply when standard gauge prototypes are modeled. It is also possible to model narrow gauge prototype locomotives using a larger scale to operate on the above relatively standard track gauges. The appropriate scales can be easily calculated from the track gauges of the model and the prototype.
Live Steam models typically model all of the appropriate aspects of a real steam locomotive, including the fire (coal or oil fired, occasionally propane is substituted), a boiler (copper on small models, usually steel on large models), cylinders, valve gear with reversing means (Stephenson, Walshearts, etc.), injectors for boiler feed (sometimes augmented or replaced by axle or reciprocating steam pumps), etc. Few if any modelers try to model automatic coal feeders.
Track for the larger gauges (7 1/4" -7 1/2", usually 4 3/4" - 5") is laid directly on the ground. Ballast is used, similar to prototype practice. Smaller gauges (3 1/2", some 4 3/4" - 5") usually use elevated track, about 3' above ground. The larger gauges are frequently ridden sitting directly on the tender, while the smaller gauges use a riding car, which is typically a flat car coupled directly behind the tender where the operator can reach the controls and tend the fire, etc.
Live steam railroading is frequently done in conjunction with live steam clubs, which typically own or otherwise have access to a plot of land on which layouts of one or more of the standard gauge track sizes are laid. Clubs also sometimes provide storage facilities for the engines, which can get quite heavy, particularly in the larger scales. Lists of clubs (worldwide), as well as a significant amount of other information about the hobby, are available in various live steam magazines:
With the exception of Gauge 1, most live steam locomotives are hand built. Many sets of suitable drawings exist, and in many cases rough castings of some parts can be purchased. However, the construction of a live steam locomotive is still as much a hobby of amateur machining (or in some cases a commercial machining business) as a railroad hobby. Costs can range from a few hundred dollars (US), if you scrounge materials and improvise a great deal (and if your time is free) to tens or even hundreds of thousands if you buy a complete locomotive or commission to have one built. The shop required to build one yourself can range from a small lathe (swings of 6-9" D.) with a milling attachment to a fully equipped machine shop, depending on the size and complexity of the model, and to some extent the time you are willing to expend to "make do".
Although the name implies operation by steam, there are also models of diesels and electrics commonly built in the same scales and gauges. These typically use automobile batteries or small gasoline engines, either with hydraulic transmissions or alternator/motor arrangements. Another branch of the hobby involves other live steam models, such as steamboats, steam tractors, steam cars or stationary steam engines.
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