Is no one going to answer the original question?
In the days of deseasel I know a geep of some type typically sat just north of the Union depot out in the open. In steam it seems there was an extensive yard system south of Colorado Avenue (and Monument Creek) on the east bank of Fountain Creek where it bent SE-ward. This was also the location of the Shortline's (CS&CCRR) terminal and is now the location of the big "downtown" power plant. Of course the Midland Terminal and CM yards were off to the west where the Van Brigle Pottery works is now located (in the old round house). And then on the east side of downtown were the Santa Fe / C&S yards. But I too do not know where the Rio Grunge serviced and "kept" its switcher.
Derrell