This kind of thing was "standard" on almost all C&S narrow gauge locomotives, although the pigtail is something I've never seen before.
Anyway, a glance through a bunch of pictures of C&S motive power will reveal steam hoses often wrapped around the sand dome for all of the reasons Herb listed. The steam valve was often on top of the dome, sometimes the pipe which supplied it ran through the sheet metal cover on the steam dome, like on 74 (at the rear). Look hard enough, you'll always find it somewhere.
Interesting shot, thanks.
Mike