FYI.
According to the information on the Geared Steam Locomotive Works web site the 3-truck models of the Heisler were among the largest (70 - 90 tons) the company offered, so the Rivarossi model may not be all that outsized.
Here is a link to the article: http://www.gearedsteam.com/heisler/heisler.htm
I have a collection of Rivarossi locomotives, some dating back to the 80's. All of them are still running, some better than others.