Bart, Charlie, and the other black railroad workers, when asked to sing a "Good ole' nigger work song", ultimately trick their white bosses into singing instead. First, they sing an awesome a cappella version of the Cole Porter song "I Get a Kick Out of You". Then when Lyle demands they sing "Swing low Sweet Chariot" then "Camp Town Ladies" instead, they pretend not to know it. This leads to the white bosses demonstrating by singing the song and dancing around like idiots, oblivious to the black, Chinese and Irish workers laughing, right when Taggert arrives and yells at them.
And then, just to drive the point home about how clueless the bosses are, Bart and Charlie sing "Camptown Ladies" while going off on the hand cart.
When all the townspeople are about to kill Bart for being a black sheriff, he stops them by taking himself hostage.
Which is just a part of his Guile Hero journey of becoming the sheriff they'll listen to. Can we have a Crowning Character of Awesome?
Harriet Van Johnson taking out one of the outlaws with a single punch.
Harriet: You son of bitch! (knocks man over when she punches him)
The railroad workers volunteer to save the town in exchange for some land - when the town grudgingly okays but adds "but we don't want the Irish!" the black and Chinese workers won't have it. The town says "Aww, prairie shit...everybody!" Yes.
The scene where Black Bart and the Waco Kid stand up to Taggart and his men at the railroad. After an hour of black characters passively accepting racial abuse, Bart tells Taggart to "watch that 'boy' shit, redneck." As that villains line up to kill Bart, there's real tension in that scene, complete with dramatic music, as if they might actually Just Shoot Him. And saving the hero is up to the Waco Kid, a character we don't quite believe in yet. He proceeds to blast the guns out of each of the bad guys' hands so fast it looks like he didn't even move. A brilliant scene on many levels.
Bart: Well, don't just stand there looking stupid grasping your hands in pain — how about a little [cocks his gun] applause for the Waco Kid? [Villains applaud sheepishly]
Bart riding out of the back lot after Hedley while the main theme blares may be the most heroic moment in the film.
Brains over brawn or when Bart stops trying to imitate the style of Gary Cooper and instead takes the tactics of Bugs Bunny: Bart delivers a "candygram for Mongo." As he saunters out, the first half of the Looney Tunes stinger plays. Mongo opens the box and gets a powder blast in the face for his trouble. Then, as the screen completely fills, we get the other half of the stinger. The horse was probably pleased.