Tim,
that's a new one on me, looks like a cross(to get around patents) of the Buda #28 column Highswstand and a Racor that CB&Q used. F&S usually means Frog & Switch, I wonder if preceding letters have been ground off. F&S is a current company doing RR supply of same in Pennsylvania but that doesn't mean they're not a newer start-up using that moniker.
As for the correct targets, that would be C&S but S.G., I've never seen that version on any C&Sng lines.
You'd have to start looking at East of the Front Range photos to define that further. CRRM had(has?) a row of various Stands of differing makes and sizes in the rear of the CB&Q Northern, can't say I'd remember if that shape was in there as I only took video of that row and that's now unviewable to me. Mind you, there was no id as to where those particular stands came from or what road used same and I was only interested in the Elliot F&S and Star Highstands at the time.
Is there a CB&Q Historical Soc. ? If so then that would be your best id resource.
UpSideDownC
in New Zealand