Steve,  I don't know if Royal American Shows had more than one large
organ, but it sounds like the organ might have been the 89-keyless
Grand Gavioli organ.  There is a picture of it on one of my web pages
that I took a few years back when the organ travelled to a fair out
where I live.  The address is
http://hometown.aol.com/gavioli89/organ.html

This organ is fully restored and located in Baraboo, Wisconsin at the
Circus World Museum. It is played during the warmer months on a daily
basis.  They have recordings of the organ as well available.  Hope this
helps.

Bill Griswold