I make no pretensions at being a locomotive expert. I've built just one, and that was a mongrelish little narrow-gauger. The General is only the second engine I've altered. I'm merely telling you what I did to transform the General into something more modern. It is a simple alteration, costing little more than $1, the only additions being a two-piece boiler, a boiler front, and a stack.
E. L. Moore summarizes his conversion of Mantua's General to something more likely to be in operation in the early 20th century. His Welish-American hybrid locomotive was likely too freelanced in appear in a magazine; however, the General conversion was possibly considered more plausible, so it was publishable.
Photos of the Elizabeth Valley RR show pictures of a few different locomotives unlike the Eagleroost & Koontree where I've only seen one so far. One of the Elizabeth Valley locos was a conversion and got featured in the March 1962 issue of Model Trains, in an article called A new look for the Old General, where E. L. Moore discussed converting Mantua's General to something similar to the locomotives featured in Florida Woodburners that appeared in the March 1951 issue of Trains.