Once again, the Little House books provide us with some social history. When Laura Ingalls and Manzo Wilder were courting, the big winter treat was to run a sleigh down the main street of town after church on a Sunday. The street would be watered on Saturday night so the surface would be freshly frozen and fast.
A trotting horse that could do a measured mile in 2 minutes, 40 seconds was going 22-1/2 mph. A sleigh has less friction than a cart, so it went even faster on the straightaway. Racing up and down in a sleigh was as fast as a normal human could expect to go in those days. For the boys, a chance to show off; for the girls, a thrilling ride.
And the horse has no name; "bob tail" [sic] and "lean and lank" are epithets, not names -- not capitalized in the original sheet music.