RivaRossi started around 1948 to make models of steamlocomotives for the American market.
During some 50 years they made about 25 different types, most of these in various liveries.
Here is a picture presentation, in approximate order of year of introduction, of all the different types, but not all liveries, from my collection.
Information on the RivaRossi production can be found on the Rivarossi Memory website: http://www.rivarossimemory.it/index.htm