The Pony Express War by Gary McCarthy
Look sharp, hit hard - that's the Derby Man's style. He's a fast-moving mountain of muscle who throws himself into the thick of the West's greatest adventures - like the Pony Express, a grueling 2,000 mile race through hell. The pace and terrain are deadly enough but vengeful Paiute warriors and murdering saboteurs led by a sadistic giant threaten to turn the route into a trail of blood.
Then one man with the guts to save the Pony Express stepped forward - the Derby Man. It's the Derby Man and the glory-riders in a race against Indians, treachery and death.