Geese(Gooses?) Again

The thread below got me to thinking....a dangerous thing when I'm supposed to be working instead of perusing the NGDF.
The "Galloping Goose" moniker has mostly been used synonomously with the RGS motors and the similar San Cristobal RR unit. M.H.Farrel attributed the term to the wife of a RGS employee.
However.......
Thinking back 35 years or more, I can recall my grandparents' stories of depression-era homesteading in west-central Idaho, and remember them talking about catching the "galloping goose" for accasional trips to the county seat. Their "goose" was a McKeen Motor car that ran on the Pacific & Idaho Northern, a standard-gauge short line that ran North from Weiser, ID.
The RGS Geese were built beginning around 1930, and my Grandmother's story dates to about the same time. It seems unlikely, then, that the term "galloping goose" could have originated with the RGS and come into common usage across the remote west in so short a time.
I submit then, that "Galloping Goose" did not originate with the RGS motors but probably predates them by a good bit. I've never heard the term used in an Eastern context, so would suspect it's an old western colloquialism; a generic term for any rail bus or rail motor car. It may have even originated with the McKeen cars which do have a most distinctive appearance.
Any thoughts, arguements, takers,??........hmmm, this one might ruffle a few feathers........
J