I am not a Snowplow guru (you have to talk to Jerry Day or Jim Eherenberger for that). I do understand, however, that the Jull Plow was manufactured in some quantity and that not only the CB&Q and ATSF had them, but the UP did also.
I ran across an engineering drawing some time ago for a new body to be built for an existing UP Jull plow.
The Jull may have been an abject failure between St. Elmo and Atlantic, but it seemed to work on other railroads.
If you read the account of the snowplow trials carefully, you will find that much of the Jull's problems were attributed to having so much weight on such light rail. It's not that the machine couldn't do the job that it was designed to do, it just wouldn't stay on the track.
Since I am about 180 miles from any reference material and am relying on memory, it seems to ring a bell that the Jull used during the snowplow trials was a broad gauge machine that was placed on 3' gauge trucks as well.
Rick