Los Angeles Live Steamers

The Los Angeles Live Steamers Railroad Museum (LALSRM) is a non-profit 501(c)(3) public benefit corporation that was founded in 1956. It was started by train enthusiasts for the purpose of educating people in railroad history and lore and also to further the avocation of live steam, gas-mechanical and electronic railroad technology.

Standards
From Large-scale Model Railroading, page 19


 * Generally accepted in the United States is a weight standard adopted by the Los Angeles Live Steamers. This rule is that no axle on a seven and one-half inch gauge train may carry more than 425 pounds of weight.  Few locomotives come even close to this figure, but it should be kept in mind when considering construction of more modern types of steamers.