https://en.wikipedia.org/wiki/Battle_of_Olustee
Black troops in the Massachusetts 54th and the 35th USCT, covered the retreat of defeated Union soldiers at the Battle of Olustee Florida, February 1864, averting total catastrophe, as Commdr. Gen Gilmore's orders had been violated by Gen, Seymour, who had been instructed not to go into the interior.
More spectacularly, the 54th Massachusetts countermarched 10 miles to rope-pull a broken Union train carrying wounded white Union troops to safety about 40 miles away, in Jacksonville, aided by horses for about 10 miles, from Ft. Finnegan which surely made these over-taxed veterans glad!